SELECT 
  pfv.variant_id, 
  pfv.position, 
  pfvd.variant 
FROM 
  cscart_product_feature_variants AS pfv 
  INNER JOIN cscart_product_feature_variant_descriptions AS pfvd ON pfv.variant_id = pfvd.variant_id 
  AND pfvd.lang_code = 'vi' 
WHERE 
  pfv.variant_id IN (
    68322, 68323, 68341, 68340, 68339, 68338, 
    68342, 68882, 68883, 68896, 68897, 
    81031, 69620, 69619, 70814, 73500, 
    73501, 74795, 75729, 75736, 75730, 
    75731, 75732, 75733, 75734, 75735, 
    78288, 78289, 81033, 81032, 81034, 
    82207, 82217, 82218, 82219, 82220, 
    82222, 82223, 82224, 82208, 82209, 
    82210, 82211, 82212, 82213, 82214, 
    82216, 86164, 86163, 87193, 87603, 
    87608, 87606, 87607, 87609, 87605, 
    87604, 87610, 87611, 87612, 87613
  )

Query time 0.00195

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "pfv",
          "access_type": "range",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["variant_id"],
          "rows": 61,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (68322,68323,68341,68340,68339,68338,68342,68882,68883,68896,68897,81031,69620,69619,70814,73500,73501,74795,75729,75736,75730,75731,75732,75733,75734,75735,78288,78289,81033,81032,81034,82207,82217,82218,82219,82220,82222,82223,82224,82208,82209,82210,82211,82212,82213,82214,82216,86164,86163,87193,87603,87608,87606,87607,87609,87605,87604,87610,87611,87612,87613)"
        }
      },
      {
        "table": {
          "table_name": "pfvd",
          "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": "pfvd.lang_code = 'vi'"
        }
      }
    ]
  }
}