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 (
    21426, 21430, 24952, 21217, 20599, 24214, 
    20604, 23648, 23649, 23148, 21913, 
    20608, 22677, 20347, 20576, 21915, 
    21473, 21475, 19605, 20607, 20609
  ) 
  AND pfv.product_id IN (
    22534, 1835, 48772, 2150, 19270, 41334, 
    3528, 1408, 29698, 1058, 19289, 1838, 
    4236, 3563, 1056, 1764, 1763, 6617, 
    3525, 3523
  ) 
  AND pfv.lang_code = 'vi'

Query time 0.14030

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": 453,
          "filtered": 0.035664216,
          "attached_condition": "pfv.feature_id in (21426,21430,24952,21217,20599,24214,20604,23648,23649,23148,21913,20608,22677,20347,20576,21915,21473,21475,19605,20607,20609) and pfv.product_id in (22534,1835,48772,2150,19270,41334,3528,1408,29698,1058,19289,1838,4236,3563,1056,1764,1763,6617,3525,3523) 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'"
        }
      }
    ]
  }
}