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 (
    68392, 68391, 68390, 68393, 68389, 69908, 
    69907, 69909, 69911, 69910, 69914, 
    69913, 69915, 69917, 69916, 69918, 
    69920, 69919, 69923, 69922, 69924, 
    69926, 69932, 69931, 69933, 69935, 
    69934, 69936, 74066, 74065, 74067, 
    74251, 74250, 74249, 74252, 74799, 
    74800, 74801, 74802, 74803, 74804, 
    75211, 75210, 75217, 75216, 76705, 
    76704, 76703, 76706, 85246, 85245, 
    85248, 85247, 85244, 85250, 85249, 
    85251, 85252, 85253, 85254, 86179, 
    86180, 86178, 86187, 86186, 86185, 
    86184, 86183, 86182, 86181, 86197, 
    86189, 86196, 86195, 86194, 86193, 
    86192, 86191, 86190, 86188, 84152, 
    87604, 84154, 87603, 87602, 87601, 
    84156, 84153
  )

Query time 0.01419

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": 88,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (68392,68391,68390,68393,68389,69908,69907,69909,69911,69910,69914,69913,69915,69917,69916,69918,69920,69919,69923,69922,69924,69926,69932,69931,69933,69935,69934,69936,74066,74065,74067,74251,74250,74249,74252,74799,74800,74801,74802,74803,74804,75211,75210,75217,75216,76705,76704,76703,76706,85246,85245,85248,85247,85244,85250,85249,85251,85252,85253,85254,86179,86180,86178,86187,86186,86185,86184,86183,86182,86181,86197,86189,86196,86195,86194,86193,86192,86191,86190,86188,84152,87604,84154,87603,87602,87601,84156,84153)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}