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 (
    298, 488, 52, 53, 54, 222, 55, 5474, 5473, 
    345, 56, 248, 57, 205, 518, 236, 392, 
    58
  )

Query time 0.00049

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "p",
      "access_type": "range",
      "possible_keys": ["PRIMARY", "idx_group_id"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["product_id"],
      "rows": 18,
      "filtered": 100,
      "index_condition": "p.product_id in (298,488,52,53,54,222,55,5474,5473,345,56,248,57,205,518,236,392,58)"
    },
    "table": {
      "table_name": "g",
      "access_type": "eq_ref",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["id"],
      "ref": ["herbaria_cscart_4_18.p.group_id"],
      "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": ["herbaria_cscart_4_18.p.group_id"],
      "rows": 1,
      "filtered": 100
    }
  }
}