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 (
    69917, 69916, 69918, 69923, 69922, 69924, 
    71578, 71576, 71577, 71831, 71830, 
    71829, 71828, 71827, 73448, 73447, 
    73446, 73500, 73501, 74243, 74242, 
    74241, 74244, 74259, 74258, 74257, 
    74260, 75729, 75736, 75730, 75731, 
    75732, 75733, 75734, 75735, 78331, 
    78332, 79034, 79035, 82441, 84391, 
    84392, 84393, 84394, 84395, 85607, 
    85608, 85609, 86656, 86657, 86658, 
    86659, 86660, 86661, 86662
  )

Query time 0.00174

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": 55,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (69917,69916,69918,69923,69922,69924,71578,71576,71577,71831,71830,71829,71828,71827,73448,73447,73446,73500,73501,74243,74242,74241,74244,74259,74258,74257,74260,75729,75736,75730,75731,75732,75733,75734,75735,78331,78332,79034,79035,82441,84391,84392,84393,84394,84395,85607,85608,85609,86656,86657,86658,86659,86660,86661,86662)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}