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 (
    70045, 70044, 70043, 70042, 70041, 70046, 
    70057, 70056, 70055, 70054, 70058, 
    70053, 70072, 70071, 70070, 70069, 
    70068, 70067, 70073, 70066, 70870, 
    70869, 70868, 70867, 70871, 70995, 
    70994, 70993, 70996, 70999, 70998, 
    70997, 71000, 71488, 71487, 71489, 
    78424, 78423, 78425, 78422, 79217, 
    79218, 79219, 79226, 79227, 79228, 
    79248, 79249, 79250, 79260, 81506, 
    81505, 81507, 81508, 81601, 81610, 
    81611, 81612, 81613, 81614, 81615, 
    81616, 81617, 81602, 81603, 81604, 
    81605, 81606, 81607, 81608, 81609, 
    82330, 82331, 82332, 84325, 84326, 
    84327, 84328, 84413, 84414, 84415, 
    84416, 84417
  )

Query time 0.01546

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": 83,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (70045,70044,70043,70042,70041,70046,70057,70056,70055,70054,70058,70053,70072,70071,70070,70069,70068,70067,70073,70066,70870,70869,70868,70867,70871,70995,70994,70993,70996,70999,70998,70997,71000,71488,71487,71489,78424,78423,78425,78422,79217,79218,79219,79226,79227,79228,79248,79249,79250,79260,81506,81505,81507,81508,81601,81610,81611,81612,81613,81614,81615,81616,81617,81602,81603,81604,81605,81606,81607,81608,81609,82330,82331,82332,84325,84326,84327,84328,84413,84414,84415,84416,84417)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}