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 (
    70249, 70248, 70247, 70246, 70245, 70244, 
    70243, 70242, 70241, 71610, 71609, 
    71608, 71607, 71606, 71605, 71604, 
    71603, 71611, 71616, 71614, 71613, 
    71612, 71615, 71621, 71619, 71618, 
    71617, 71620, 74232, 74231, 74230, 
    75631, 75629, 75630, 76705, 76704, 
    76703, 76706, 81621, 81601, 81609, 
    81608, 81607, 81606, 81605, 81604, 
    81603, 81602, 81617, 81616, 81615, 
    81614, 81613, 81612, 81611, 81610, 
    81622, 81623, 81624, 81625, 81643, 
    81644, 84725, 84724, 82134, 82133, 
    82135, 82657, 82658, 82660, 82661, 
    84341, 84342, 86606, 86607, 86608
  )

Query time 0.01878

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": 76,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (70249,70248,70247,70246,70245,70244,70243,70242,70241,71610,71609,71608,71607,71606,71605,71604,71603,71611,71616,71614,71613,71612,71615,71621,71619,71618,71617,71620,74232,74231,74230,75631,75629,75630,76705,76704,76703,76706,81621,81601,81609,81608,81607,81606,81605,81604,81603,81602,81617,81616,81615,81614,81613,81612,81611,81610,81622,81623,81624,81625,81643,81644,84725,84724,82134,82133,82135,82657,82658,82660,82661,84341,84342,86606,86607,86608)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}