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 (
    13860, 13876, 13879, 13896, 13895, 13899, 
    13861, 13857, 13859, 13858, 13897, 
    13866, 13894, 13873, 13889, 13885, 
    13884, 13892, 13891, 13890, 13893
  )

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.08246491,
    "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": 21,
          "cost": 0.02300071,
          "filtered": 100,
          "attached_condition": "p.product_id in (13860,13876,13879,13896,13895,13899,13861,13857,13859,13858,13897,13866,13894,13873,13889,13885,13884,13892,13891,13890,13893)"
        }
      },
      {
        "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": 21,
          "rows": 1,
          "cost": 0.03986176,
          "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": 21,
          "rows": 1,
          "cost": 0.01960244,
          "filtered": 100
        }
      }
    ]
  }
}