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 (
    68903, 68902, 68901, 68904, 71071, 71072, 
    71341, 71339, 71338, 71337, 71336, 
    71335, 71334, 71333, 71332, 71331, 
    71342, 71557, 71556, 74646, 74657, 
    74656, 74655, 74654, 74653, 74652, 
    74805, 74806, 75125, 75124, 75123, 
    75122, 75121, 75126, 75729, 75736, 
    75730, 75731, 75732, 75733, 75734, 
    75735, 77111, 77110, 79199, 79198, 
    81505, 81506, 81507, 81508, 82141, 
    82149, 82153, 82164, 82154, 82162, 
    82160, 82158, 82167, 82166, 82165, 
    84766, 84293, 84391, 84392, 84393, 
    84394, 84395, 84426, 84427, 84428, 
    84429, 85306, 85307, 85308, 85305, 
    85318, 85319, 85317, 85635, 85629, 
    85634, 85626, 85636, 85627, 85628, 
    85633, 85632, 85631, 85630, 85738, 
    85746, 85747, 85748, 85739, 85740, 
    85741, 85742, 85743, 85744, 85745, 
    85749, 85757, 85758, 85759, 85750, 
    85751, 85752, 85753, 85754, 85755, 
    85756, 86656, 86657, 86658, 86659, 
    86660, 86661, 86662, 86882, 86883
  )

Query time 0.02263

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": 121,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (68903,68902,68901,68904,71071,71072,71341,71339,71338,71337,71336,71335,71334,71333,71332,71331,71342,71557,71556,74646,74657,74656,74655,74654,74653,74652,74805,74806,75125,75124,75123,75122,75121,75126,75729,75736,75730,75731,75732,75733,75734,75735,77111,77110,79199,79198,81505,81506,81507,81508,82141,82149,82153,82164,82154,82162,82160,82158,82167,82166,82165,84766,84293,84391,84392,84393,84394,84395,84426,84427,84428,84429,85306,85307,85308,85305,85318,85319,85317,85635,85629,85634,85626,85636,85627,85628,85633,85632,85631,85630,85738,85746,85747,85748,85739,85740,85741,85742,85743,85744,85745,85749,85757,85758,85759,85750,85751,85752,85753,85754,85755,85756,86656,86657,86658,86659,86660,86661,86662,86882,86883)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}