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 (
    444839, 428245, 418635, 426766, 438143, 
    427476, 438277, 423983, 418826, 451985, 
    420812, 455665, 404060, 455720, 420563, 
    416787, 428711, 460118, 458461, 403343, 
    405043, 402986, 417129, 414508, 403905, 
    410883, 408899, 408775, 440269, 435840, 
    444141, 410125, 453374, 429849, 427100, 
    430100, 427619, 444547, 432847, 403496, 
    431636, 455406, 435103, 415659, 443503, 
    401160, 406539, 408349
  )

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.03140489,
    "nested_loop": [
      {
        "table": {
          "table_name": "g",
          "access_type": "index",
          "possible_keys": ["PRIMARY"],
          "key": "idx_group_code",
          "key_length": "387",
          "used_key_parts": ["code"],
          "loops": 1,
          "rows": 2,
          "cost": 0.00693929,
          "filtered": 100,
          "using_index": true
        }
      },
      {
        "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": ["u985510652_ecartify.g.id"],
          "loops": 2,
          "rows": 1,
          "cost": 0.00527872,
          "filtered": 100
        }
      },
      {
        "table": {
          "table_name": "p",
          "access_type": "ref",
          "possible_keys": ["PRIMARY", "idx_group_id"],
          "key": "idx_group_id",
          "key_length": "3",
          "used_key_parts": ["group_id"],
          "ref": ["u985510652_ecartify.g.id"],
          "loops": 2,
          "rows": 8,
          "cost": 0.01918688,
          "filtered": 100,
          "index_condition": "p.product_id in (444839,428245,418635,426766,438143,427476,438277,423983,418826,451985,420812,455665,404060,455720,420563,416787,428711,460118,458461,403343,405043,402986,417129,414508,403905,410883,408899,408775,440269,435840,444141,410125,453374,429849,427100,430100,427619,444547,432847,403496,431636,455406,435103,415659,443503,401160,406539,408349)"
        }
      }
    ]
  }
}