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 (
    70950, 70949, 70951, 71488, 71487, 71489, 
    71492, 71490, 71493, 71491, 71508, 
    71509, 71511, 71510, 71513, 71512, 
    71514, 71524, 71522, 71526, 71525, 
    71523, 77913, 78424, 78423, 78425, 
    78422, 79217, 79218, 79219, 79226, 
    79227, 79228, 79248, 79249, 79250, 
    81534, 81535, 81538, 81601, 81610, 
    81611, 81612, 81613, 81614, 81615, 
    81616, 81617, 81602, 81603, 81604, 
    81605, 81606, 81607, 81608, 81609, 
    82362, 82363, 82364, 82365, 82366, 
    82367, 82372, 82373, 82374, 82375, 
    82383, 82384, 82385, 82402, 82406, 
    82405, 82404, 82403, 82413, 82414, 
    82416, 82417, 82418, 83946, 83947, 
    83948, 83949, 83950, 83970, 83969, 
    83968, 83967, 83966, 83965, 83964, 
    83961, 83960, 83954, 83955, 83956, 
    83957, 83958, 83959, 84325, 84326, 
    84327, 84328, 85227, 85228, 85229, 
    85230, 85231, 85232, 85233, 85234, 
    86218, 86219, 86220
  )

Query time 0.00882

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": 114,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (70950,70949,70951,71488,71487,71489,71492,71490,71493,71491,71508,71509,71511,71510,71513,71512,71514,71524,71522,71526,71525,71523,77913,78424,78423,78425,78422,79217,79218,79219,79226,79227,79228,79248,79249,79250,81534,81535,81538,81601,81610,81611,81612,81613,81614,81615,81616,81617,81602,81603,81604,81605,81606,81607,81608,81609,82362,82363,82364,82365,82366,82367,82372,82373,82374,82375,82383,82384,82385,82402,82406,82405,82404,82403,82413,82414,82416,82417,82418,83946,83947,83948,83949,83950,83970,83969,83968,83967,83966,83965,83964,83961,83960,83954,83955,83956,83957,83958,83959,84325,84326,84327,84328,85227,85228,85229,85230,85231,85232,85233,85234,86218,86219,86220)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}