SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '' 
    OR cscart_product_descriptions.short_description IS NULL, 
    cscart_product_descriptions.full_description, 
    ''
  ) AS full_description 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    98446, 98449, 98450, 98452, 98455, 98485, 
    98486, 98487, 98488, 98489, 98491, 
    98493, 98494, 98495, 98503, 98504, 
    98505, 98506, 98507, 98508, 99509, 
    99510, 99513, 99514, 99517, 99518, 
    100789, 100790, 100791, 100792, 100793, 
    100794, 100795, 100796, 100797, 100798, 
    100799, 100800, 100801, 100802, 100803, 
    100804, 100805, 100806, 100807, 100808, 
    100809, 100810, 100811, 100812, 100813, 
    100814, 100815, 100816, 100817, 100818, 
    100819, 100820, 100821, 100822, 100823, 
    100824, 100825, 100826, 100827, 100828, 
    100829, 100830, 100831, 100832, 100833, 
    100834, 100835, 100836, 100837, 100838, 
    100839, 100840
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00125

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "35.14"
    },
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "product_id"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id",
        "lang_code"
      ],
      "key_length": "9",
      "rows_examined_per_scan": 78,
      "rows_produced_per_join": 78,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "27.34",
        "eval_cost": "7.80",
        "prefix_cost": "35.14",
        "data_read_per_join": "297K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (98446,98449,98450,98452,98455,98485,98486,98487,98488,98489,98491,98493,98494,98495,98503,98504,98505,98506,98507,98508,99509,99510,99513,99514,99517,99518,100789,100790,100791,100792,100793,100794,100795,100796,100797,100798,100799,100800,100801,100802,100803,100804,100805,100806,100807,100808,100809,100810,100811,100812,100813,100814,100815,100816,100817,100818,100819,100820,100821,100822,100823,100824,100825,100826,100827,100828,100829,100830,100831,100832,100833,100834,100835,100836,100837,100838,100839,100840)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}