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 (
    100579, 100580, 100581, 100582, 100583, 
    100584, 100585, 100586, 100587, 100588, 
    100589, 100590, 100591, 100592, 100593, 
    101047, 101048, 101049, 101050, 101051, 
    101052, 101053, 101574, 101575, 101576, 
    101577, 101578, 101579, 101580, 101581, 
    101582, 101583, 101584, 101585, 101586, 
    101587, 101588, 101589, 101590, 101591, 
    101592, 101593, 101594, 101595, 101596, 
    101597, 101598, 101599, 101600, 101601, 
    101602, 101603, 101604, 101605, 101606, 
    101607, 101608, 101609, 101610, 101611, 
    101612, 101613, 101614, 101615, 101616, 
    101617, 101618, 101619, 101620, 101621, 
    101622, 101623, 101624
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00067

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "32.88"
    },
    "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": 73,
      "rows_produced_per_join": 73,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "25.58",
        "eval_cost": "7.30",
        "prefix_cost": "32.88",
        "data_read_per_join": "278K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (100579,100580,100581,100582,100583,100584,100585,100586,100587,100588,100589,100590,100591,100592,100593,101047,101048,101049,101050,101051,101052,101053,101574,101575,101576,101577,101578,101579,101580,101581,101582,101583,101584,101585,101586,101587,101588,101589,101590,101591,101592,101593,101594,101595,101596,101597,101598,101599,101600,101601,101602,101603,101604,101605,101606,101607,101608,101609,101610,101611,101612,101613,101614,101615,101616,101617,101618,101619,101620,101621,101622,101623,101624)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}