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 (
    20695, 20466, 23444, 23445, 20040, 21265, 
    23755, 21267, 23757, 19842, 20032, 
    19841, 20034, 20038, 19843, 19839, 
    20036, 23626
  ) 
  AND pfv.product_id IN (
    3286, 3872, 1401, 5455, 36781, 36834, 
    5958, 5476, 5959, 5472, 5462, 5957, 
    5961, 5467, 35733
  ) 
  AND pfv.lang_code = 'vi'

Query time 0.01395

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": 302,
          "filtered": 0.513714671,
          "attached_condition": "pfv.feature_id in (20695,20466,23444,23445,20040,21265,23755,21267,23757,19842,20032,19841,20034,20038,19843,19839,20036,23626) and pfv.product_id in (3286,3872,1401,5455,36781,36834,5958,5476,5959,5472,5462,5957,5961,5467,35733) 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'"
        }
      }
    ]
  }
}