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 (
    84768, 84781, 84790, 87503, 87513, 87519, 
    87529, 88442, 88451, 88459, 88468, 
    88476, 88484, 87462, 88173, 88221, 
    85671, 85691, 85703, 85715, 88521, 
    88552, 89838, 89890, 89962, 91528, 
    88445, 85679, 88496, 91438, 91452, 
    87516, 87532, 88448, 88465, 88481, 
    88793, 84763, 88784, 88142, 88145, 
    88171, 88219, 89103, 89111, 88069, 
    88785, 90830, 84772, 84785, 84794, 
    85668, 85688, 85700, 85712, 88550, 
    88593, 88769, 87546, 87549, 88402, 
    88405, 89786, 89836, 89888, 89960, 
    91526, 85676, 87535, 88398, 88491, 
    91433, 91447, 84776, 87878, 88443, 
    90816, 88697, 88744, 88075, 88197, 
    88209, 87515, 87531, 84696, 88938, 
    88549, 89018, 84699, 88516, 88519, 
    89109, 89116, 89784, 88195, 88207
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00094

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "43.24"
    },
    "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": 96,
      "rows_produced_per_join": 96,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "33.64",
        "eval_cost": "9.60",
        "prefix_cost": "43.24",
        "data_read_per_join": "366K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (84768,84781,84790,87503,87513,87519,87529,88442,88451,88459,88468,88476,88484,87462,88173,88221,85671,85691,85703,85715,88521,88552,89838,89890,89962,91528,88445,85679,88496,91438,91452,87516,87532,88448,88465,88481,88793,84763,88784,88142,88145,88171,88219,89103,89111,88069,88785,90830,84772,84785,84794,85668,85688,85700,85712,88550,88593,88769,87546,87549,88402,88405,89786,89836,89888,89960,91526,85676,87535,88398,88491,91433,91447,84776,87878,88443,90816,88697,88744,88075,88197,88209,87515,87531,84696,88938,88549,89018,84699,88516,88519,89109,89116,89784,88195,88207)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}