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 (
    71589, 71588, 71587, 71586, 71585, 71590, 
    71596, 71595, 71594, 71593, 71592, 
    71591, 71597, 74801, 74802, 75765, 
    75763, 75764, 75766, 75769, 75767, 
    75768, 75770, 81679, 81683, 81684, 
    81910, 81913, 81914, 81915, 81916, 
    81911, 81912, 85255, 85256, 85257, 
    86261, 86260, 86259, 86258, 86257, 
    86256, 86606, 86607, 86608, 86706, 
    86711, 86712, 86713, 86714, 86715, 
    86707, 86708, 86709, 86710, 86851, 
    86852, 86853, 87124
  )

Query time 0.00639

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": 59,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (71589,71588,71587,71586,71585,71590,71596,71595,71594,71593,71592,71591,71597,74801,74802,75765,75763,75764,75766,75769,75767,75768,75770,81679,81683,81684,81910,81913,81914,81915,81916,81911,81912,85255,85256,85257,86261,86260,86259,86258,86257,86256,86606,86607,86608,86706,86711,86712,86713,86714,86715,86707,86708,86709,86710,86851,86852,86853,87124)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}