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, 
    70072, 70071, 70070, 70069, 70068, 
    70067, 70073, 70066, 70870, 70869, 
    70868, 70867, 70871, 70878, 70879, 
    71023, 71022, 71021, 71024, 71077, 
    71078, 73043, 73044, 73533, 73532, 
    73537, 73536, 73569, 73568, 73980, 
    73979, 73978, 73981, 75065, 75064, 
    75063, 75062, 75066, 79947, 79945, 
    79943, 80712, 80713, 80714, 80715, 
    81807, 81808, 82228, 82229, 82230, 
    82923, 86337, 86938, 86939, 86940, 
    86941, 86962, 86963, 86964, 86965
  )

Query time 0.01245

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": 66,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (70045,70044,70043,70042,70041,70046,70072,70071,70070,70069,70068,70067,70073,70066,70870,70869,70868,70867,70871,70878,70879,71023,71022,71021,71024,71077,71078,73043,73044,73533,73532,73537,73536,73569,73568,73980,73979,73978,73981,75065,75064,75063,75062,75066,79947,79945,79943,80712,80713,80714,80715,81807,81808,82228,82229,82230,82923,86337,86938,86939,86940,86941,86962,86963,86964,86965)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}