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 (
    69012, 69011, 69010, 69009, 69008, 69007, 
    69006, 69005, 69013, 69004, 69020, 
    69019, 69018, 69017, 69016, 69015, 
    69021, 69014, 70039, 70038, 70037, 
    70036, 70040, 70035, 70085, 70086, 
    70084, 70876, 70877, 71009, 71008, 
    71007, 71010, 78917, 78912, 78913, 
    78914, 78915, 78916, 80613, 80617, 
    80612, 80618, 80619, 80620, 80621, 
    80616, 80614, 80615, 81440, 81445, 
    81446, 81447, 81441, 81442, 81443, 
    81444, 81888, 81892, 81893, 81894, 
    81895, 81896, 81897, 81889, 81890, 
    81891, 81898, 81905, 81906, 81907, 
    81908, 81909, 81899, 81900, 81901, 
    81902, 81903, 81904, 81910, 81913, 
    81914, 81915, 81916, 81911, 81912, 
    81917, 81922, 81923, 81924, 81925, 
    81926, 81918, 81919, 81920, 81921, 
    87026, 87027
  )

Query time 0.00690

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 (69012,69011,69010,69009,69008,69007,69006,69005,69013,69004,69020,69019,69018,69017,69016,69015,69021,69014,70039,70038,70037,70036,70040,70035,70085,70086,70084,70876,70877,71009,71008,71007,71010,78917,78912,78913,78914,78915,78916,80613,80617,80612,80618,80619,80620,80621,80616,80614,80615,81440,81445,81446,81447,81441,81442,81443,81444,81888,81892,81893,81894,81895,81896,81897,81889,81890,81891,81898,81905,81906,81907,81908,81909,81899,81900,81901,81902,81903,81904,81910,81913,81914,81915,81916,81911,81912,81917,81922,81923,81924,81925,81926,81918,81919,81920,81921,87026,87027)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}