SELECT 
  product_id, 
  feature_id, 
  variant_id 
FROM 
  cscart_product_features_values 
WHERE 
  product_id IN (
    42077, 42078, 42079, 42080, 41713, 42081, 
    42082, 42083, 42084, 42085, 42086, 
    42087, 42088, 42089, 42090, 42091, 
    42092, 42093, 42094, 42095
  ) 
  AND feature_id IN (24257, 24256) 
  AND lang_code = 'vi'

Query time 0.00878

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_product_features_values",
          "access_type": "range",
          "possible_keys": [
            "PRIMARY",
            "fl",
            "lang_code",
            "product_id",
            "fpl",
            "idx_product_feature_variant_id"
          ],
          "key": "idx_product_feature_variant_id",
          "key_length": "12",
          "used_key_parts": ["product_id", "feature_id", "lang_code"],
          "rows": 40,
          "filtered": 100,
          "attached_condition": "cscart_product_features_values.product_id in (42077,42078,42079,42080,41713,42081,42082,42083,42084,42085,42086,42087,42088,42089,42090,42091,42092,42093,42094,42095) and cscart_product_features_values.feature_id in (24257,24256) and cscart_product_features_values.lang_code = 'vi'",
          "using_index": true
        }
      }
    ]
  }
}