SELECT 
  f.feature_id, 
  f.purpose, 
  p.product_id, 
  p.parent_product_id, 
  g.id, 
  g.code 
FROM 
  cscart_product_variation_group_features AS f 
  INNER JOIN cscart_product_variation_groups AS g ON f.group_id = g.id 
  INNER JOIN cscart_product_variation_group_products AS p ON f.group_id = p.group_id 
WHERE 
  p.product_id IN (
    238, 239, 245, 242, 243, 65, 64, 63, 66, 
    62, 134, 135, 33, 32, 246, 71, 70, 69, 
    68, 67, 155, 153, 154, 190, 189, 168, 
    167, 169, 165, 166, 86, 106, 105, 101, 
    146, 147, 145, 156, 157, 148, 149, 30, 
    29, 248, 140, 141, 144, 143
  )

Query time 0.00052

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "g",
      "access_type": "system",
      "possible_keys": ["PRIMARY"],
      "rows": 1,
      "filtered": 100
    },
    "table": {
      "table_name": "f",
      "access_type": "ref",
      "possible_keys": ["idx_group_id"],
      "key": "idx_group_id",
      "key_length": "3",
      "used_key_parts": ["group_id"],
      "ref": ["const"],
      "rows": 2,
      "filtered": 100
    },
    "block-nl-join": {
      "table": {
        "table_name": "p",
        "access_type": "ALL",
        "possible_keys": ["PRIMARY", "idx_group_id"],
        "rows": 7,
        "filtered": 100,
        "attached_condition": "p.group_id = 10 and p.product_id in (238,239,245,242,243,65,64,63,66,62,134,135,33,32,246,71,70,69,68,67,155,153,154,190,189,168,167,169,165,166,86,106,105,101,146,147,145,156,157,148,149,30,29,248,140,141,144,143)"
      },
      "buffer_type": "flat",
      "buffer_size": "1Kb",
      "join_type": "BNL"
    }
  }
}