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 (
    14011, 14012, 14013, 14014, 14015, 14016, 
    14017, 14018
  )

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.03393344,
    "nested_loop": [
      {
        "table": {
          "table_name": "p",
          "access_type": "range",
          "possible_keys": ["PRIMARY", "idx_group_id"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["product_id"],
          "loops": 1,
          "rows": 8,
          "cost": 0.00975904,
          "filtered": 100,
          "attached_condition": "p.product_id in (14011,14012,14013,14014,14015,14016,14017,14018)"
        }
      },
      {
        "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": ["u508912950_dev_2025.p.group_id"],
          "loops": 8,
          "rows": 1,
          "cost": 0.01619968,
          "filtered": 100
        }
      },
      {
        "table": {
          "table_name": "g",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["id"],
          "ref": ["u508912950_dev_2025.p.group_id"],
          "loops": 8,
          "rows": 1,
          "cost": 0.00797472,
          "filtered": 100
        }
      }
    ]
  }
}