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 (
    23620, 23621, 23618, 23619, 23249, 23250, 
    23624, 23625, 20254, 20297, 23469, 
    23470, 20031, 20298, 20030, 20293, 
    20299, 20027, 20301, 20255, 20253, 
    20300, 20029, 20302
  ) 
  AND pfv.product_id IN (
    35833, 35804, 31966, 35859, 4465, 4362, 
    33625, 5478, 4361, 5479, 4366, 4360, 
    5485, 4358, 4464, 4466, 4359, 5481, 
    4357
  ) 
  AND pfv.lang_code = 'vi'

Query time 0.08713

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": "product_id",
          "key_length": "3",
          "used_key_parts": ["product_id"],
          "rowid_filter": {
            "range": {
              "key": "fl",
              "used_key_parts": ["feature_id", "lang_code"]
            },
            "rows": 599,
            "selectivity_pct": 0.378625066
          },
          "rows": 113,
          "filtered": 2.673645973,
          "index_condition": "pfv.product_id in (35833,35804,31966,35859,4465,4362,33625,5478,4361,5479,4366,4360,5485,4358,4464,4466,4359,5481,4357)",
          "attached_condition": "pfv.feature_id in (23620,23621,23618,23619,23249,23250,23624,23625,20254,20297,23469,23470,20031,20298,20030,20293,20299,20027,20301,20255,20253,20300,20029,20302) and pfv.lang_code = 'vi'"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}