SELECT 
  cscart_products.* 
FROM 
  cscart_products 
WHERE 
  cscart_products.product_id IN (79, 78, 81)

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_products",
      "access_type": "range",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "rows": 3,
      "filtered": 100,
      "index_condition": "cscart_products.product_id in (79,78,81)"
    }
  }
}

Result

product_id product_code product_type status company_id list_price amount weight length width height shipping_freight low_avail_limit timestamp updated_timestamp usergroup_ids is_edp edp_shipping unlimited_download tracking free_shipping zero_price_action is_pbp is_op is_oper is_returnable return_period avail_since out_of_stock_actions localization min_qty max_qty qty_step list_qty_count tax_ids age_verification age_limit options_type exceptions_type details_layout shipping_params parent_product_id addon_ship_start_date
78 L0078RO9Y9 P A 1 0.00 10 0.000 0 0 0 0.00 0 1328644800 1328684302 0 N N N N Y N N Y 10 0 N N 0 default a:5:{s:16:"min_items_in_box";i:0;s:16:"max_items_in_box";i:0;s:10:"box_length";i:0;s:9:"box_width";i:0;s:10:"box_height";i:0;} 0 0
79 Z0079TIUPW P A 1 13000.00 10 0.000 0 0 0 0.00 0 1328644800 1383893667 0 N N N N Y N N Y 10 0 N N 0 default a:5:{s:16:"min_items_in_box";i:0;s:16:"max_items_in_box";i:0;s:10:"box_length";i:0;s:9:"box_width";i:0;s:10:"box_height";i:0;} 0 0
81 Y0081TT6SI P A 1 0.00 40 0.000 0 0 0 0.00 0 1328644800 1328684302 0 N N N N Y N N Y 10 0 N N 0 default a:5:{s:16:"min_items_in_box";i:0;s:16:"max_items_in_box";i:0;s:10:"box_length";i:0;s:9:"box_width";i:0;s:10:"box_height";i:0;} 0 0