SELECT 
  SQL_CALC_FOUND_ROWS (
    CASE WHEN products.parent_product_id <> 0 THEN products.parent_product_id ELSE products.product_id END
  ) AS product_id, 
  descr1.product as product, 
  companies.company as company_name, 
  MIN(
    IF(
      prices.percentage_discount = 0, 
      prices.price, 
      prices.price - (
        prices.price * prices.percentage_discount
      )/ 100
    )
  ) as price, 
  GROUP_CONCAT(
    products.product_id 
    ORDER BY 
      products.parent_product_id ASC, 
      products.product_id ASC
  ) AS product_ids, 
  GROUP_CONCAT(
    products.product_type 
    ORDER BY 
      products.parent_product_id ASC, 
      products.product_id ASC
  ) AS product_types, 
  GROUP_CONCAT(
    products.parent_product_id 
    ORDER BY 
      products.parent_product_id ASC, 
      products.product_id ASC
  ) AS parent_product_ids, 
  products.product_type, 
  products.parent_product_id, 
  cscart_product_review_prepared_data.average_rating average_rating, 
  cscart_product_review_prepared_data.reviews_count product_reviews_count 
FROM 
  cscart_products as products 
  LEFT JOIN cscart_product_descriptions as descr1 ON descr1.product_id = products.product_id 
  AND descr1.lang_code = 'ja' 
  LEFT JOIN cscart_product_prices as prices ON prices.product_id = products.product_id 
  AND prices.lower_limit = 1 
  LEFT JOIN cscart_product_prices as prices_2 ON prices.product_id = prices_2.product_id 
  AND prices_2.lower_limit = 1 
  AND prices_2.price < prices.price 
  AND prices_2.usergroup_id IN (0, 0, 1) 
  LEFT JOIN cscart_companies AS companies ON companies.company_id = products.company_id 
  INNER JOIN cscart_products_categories as products_categories ON products_categories.product_id = products.product_id 
  INNER JOIN cscart_categories ON cscart_categories.category_id = products_categories.category_id 
  AND (
    cscart_categories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_categories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_categories.usergroup_ids
    )
  ) 
  AND cscart_categories.status IN ('A', 'H') 
  LEFT JOIN cscart_product_review_prepared_data ON cscart_product_review_prepared_data.product_id = products.product_id 
  AND cscart_product_review_prepared_data.storefront_id = 0 
WHERE 
  1 
  AND products.product_id NOT IN (36) 
  AND companies.status = 'A' 
  AND prices.price >= 5814.00 
  AND prices.price <= 6426.00 
  AND (
    products.usergroup_ids = '' 
    OR FIND_IN_SET(0, products.usergroup_ids) 
    OR FIND_IN_SET(1, products.usergroup_ids)
  ) 
  AND products.status IN ('A') 
  AND prices.usergroup_id IN (0, 0, 1) 
  AND prices_2.price IS NULL 
GROUP BY 
  product_id 
ORDER BY 
  product asc, 
  products.product_id ASC 
LIMIT 
  0, 3

Query time 0.00382

JSON explain

{
  "query_block": {
    "select_id": 1,
    "filesort": {
      "sort_key": "descr1.product, products.product_id",
      "temporary_table": {
        "filesort": {
          "sort_key": "case when products.parent_product_id <> 0 then products.parent_product_id else products.product_id end",
          "temporary_table": {
            "table": {
              "table_name": "cscart_categories",
              "access_type": "index",
              "possible_keys": ["PRIMARY", "c_status", "p_category_id"],
              "key": "p_category_id",
              "key_length": "773",
              "used_key_parts": ["category_id", "usergroup_ids", "status"],
              "rows": 83,
              "filtered": 100,
              "attached_condition": "(cscart_categories.usergroup_ids = '' or find_in_set(0,cscart_categories.usergroup_ids) or find_in_set(1,cscart_categories.usergroup_ids)) and cscart_categories.`status` in ('A','H')",
              "using_index": true
            },
            "table": {
              "table_name": "products_categories",
              "access_type": "ref",
              "possible_keys": ["PRIMARY", "pt"],
              "key": "PRIMARY",
              "key_length": "3",
              "used_key_parts": ["category_id"],
              "ref": ["smscrm_edev.cscart_categories.category_id"],
              "rows": 2,
              "filtered": 99.25093842,
              "attached_condition": "products_categories.product_id <> 36",
              "using_index": true
            },
            "table": {
              "table_name": "products",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY", "status"],
              "key": "PRIMARY",
              "key_length": "3",
              "used_key_parts": ["product_id"],
              "ref": ["smscrm_edev.products_categories.product_id"],
              "rows": 1,
              "filtered": 99.19028473,
              "attached_condition": "(products.usergroup_ids = '' or find_in_set(0,products.usergroup_ids) or find_in_set(1,products.usergroup_ids)) and products.`status` = 'A'"
            },
            "table": {
              "table_name": "cscart_product_review_prepared_data",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY"],
              "key": "PRIMARY",
              "key_length": "7",
              "used_key_parts": ["product_id", "storefront_id"],
              "ref": ["smscrm_edev.products_categories.product_id", "const"],
              "rows": 1,
              "filtered": 100
            },
            "table": {
              "table_name": "descr1",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY", "product_id"],
              "key": "PRIMARY",
              "key_length": "9",
              "used_key_parts": ["product_id", "lang_code"],
              "ref": ["smscrm_edev.products_categories.product_id", "const"],
              "rows": 1,
              "filtered": 100,
              "attached_condition": "trigcond(descr1.lang_code = 'ja')"
            },
            "table": {
              "table_name": "prices",
              "access_type": "ref",
              "possible_keys": [
                "usergroup",
                "product_id",
                "lower_limit",
                "usergroup_id"
              ],
              "key": "usergroup",
              "key_length": "3",
              "used_key_parts": ["product_id"],
              "ref": ["smscrm_edev.products_categories.product_id"],
              "rows": 2,
              "filtered": 100,
              "index_condition": "prices.lower_limit = 1 and prices.usergroup_id in (0,0,1)",
              "attached_condition": "prices.price >= 5814.00 and prices.price <= 6426.00"
            },
            "table": {
              "table_name": "companies",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY"],
              "key": "PRIMARY",
              "key_length": "4",
              "used_key_parts": ["company_id"],
              "ref": ["smscrm_edev.products.company_id"],
              "rows": 1,
              "filtered": 100,
              "attached_condition": "companies.`status` = 'A'"
            },
            "table": {
              "table_name": "prices_2",
              "access_type": "ref",
              "possible_keys": [
                "usergroup",
                "product_id",
                "lower_limit",
                "usergroup_id"
              ],
              "key": "usergroup",
              "key_length": "3",
              "used_key_parts": ["product_id"],
              "ref": ["smscrm_edev.products_categories.product_id"],
              "rows": 2,
              "filtered": 97.23320007,
              "attached_condition": "trigcond(prices_2.price is null) and trigcond(prices_2.lower_limit = 1 and prices_2.price < prices.price and prices_2.usergroup_id in (0,0,1))",
              "not_exists": true
            }
          }
        }
      }
    }
  }
}