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 (
    69892, 69891, 69890, 69903, 69902, 69904, 
    69908, 69907, 69909, 69914, 69913, 
    69915, 69917, 69916, 69918, 69920, 
    69919, 69923, 69922, 69924, 69928, 
    69929, 69930, 69932, 69931, 69933, 
    69935, 69934, 69936, 74243, 74242, 
    74241, 74244, 74247, 74246, 74245, 
    74248, 74251, 74250, 74249, 74252, 
    74255, 74254, 74253, 74256, 74259, 
    74258, 74257, 74260, 74795, 74801, 
    74802, 75217, 75216, 81610, 81619, 
    81620, 81611, 81612, 81613, 81614, 
    81615, 81616, 81617, 81601, 81602, 
    81603, 81604, 81605, 81606, 81607, 
    81608, 81609, 85246, 85245, 85248, 
    85247, 85244, 86169, 86173, 86171, 
    86170, 86168, 86176, 86172, 86177, 
    86174, 86175, 86197, 86189, 86196, 
    86195, 86194, 86193, 86192, 86191, 
    86190, 86188
  )

Query time 0.00470

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": 98,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (69892,69891,69890,69903,69902,69904,69908,69907,69909,69914,69913,69915,69917,69916,69918,69920,69919,69923,69922,69924,69928,69929,69930,69932,69931,69933,69935,69934,69936,74243,74242,74241,74244,74247,74246,74245,74248,74251,74250,74249,74252,74255,74254,74253,74256,74259,74258,74257,74260,74795,74801,74802,75217,75216,81610,81619,81620,81611,81612,81613,81614,81615,81616,81617,81601,81602,81603,81604,81605,81606,81607,81608,81609,85246,85245,85248,85247,85244,86169,86173,86171,86170,86168,86176,86172,86177,86174,86175,86197,86189,86196,86195,86194,86193,86192,86191,86190,86188)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}