SELECT 
  pfv.feature_id, 
  pfv.product_id, 
  pfv.variant_id, 
  fv.position, 
  fvd.variant 
FROM 
  cscart_product_features_values AS pfv 
  INNER JOIN cscart_product_feature_variants AS fv ON pfv.feature_id = fv.feature_id 
  AND pfv.variant_id = fv.variant_id 
  INNER JOIN cscart_product_feature_variant_descriptions AS fvd ON pfv.variant_id = fvd.variant_id 
  AND fvd.lang_code = 'vi' 
WHERE 
  pfv.feature_id IN (
    21228, 21018, 20262, 23488, 22438, 20461, 
    19607, 21226, 19811, 21019, 21025, 
    20606, 19997, 20459, 20318, 21726, 
    23237, 21016, 22338, 19661
  ) 
  AND pfv.product_id IN (
    2133, 2508, 18260, 33747, 263, 3877, 
    6615, 2135, 6056, 2507, 2501, 19285, 
    5568, 3879, 4305, 23419, 31641, 2510, 
    400, 6533
  ) 
  AND pfv.lang_code = 'vi'

Query time 0.03384

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "pfv",
          "access_type": "range",
          "possible_keys": [
            "PRIMARY",
            "fl",
            "variant_id",
            "lang_code",
            "product_id",
            "fpl",
            "idx_product_feature_variant_id"
          ],
          "key": "PRIMARY",
          "key_length": "6",
          "used_key_parts": ["feature_id", "product_id"],
          "rows": 432,
          "filtered": 0.027156686,
          "attached_condition": "pfv.feature_id in (21228,21018,20262,23488,22438,20461,19607,21226,19811,21019,21025,20606,19997,20459,20318,21726,23237,21016,22338,19661) and pfv.product_id in (2133,2508,18260,33747,263,3877,6615,2135,6056,2507,2501,19285,5568,3879,4305,23419,31641,2510,400,6533) and pfv.lang_code = 'vi'",
          "using_index": true
        }
      },
      {
        "table": {
          "table_name": "fv",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY", "feature_id"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["variant_id"],
          "ref": ["dev_db.pfv.variant_id"],
          "rows": 1,
          "filtered": 100,
          "attached_condition": "fv.feature_id = pfv.feature_id"
        }
      },
      {
        "table": {
          "table_name": "fvd",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "9",
          "used_key_parts": ["variant_id", "lang_code"],
          "ref": ["dev_db.pfv.variant_id", "const"],
          "rows": 1,
          "filtered": 100,
          "index_condition": "fvd.lang_code = 'vi'"
        }
      }
    ]
  }
}