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 (
    96905, 96906, 96907, 96908, 96909, 96910, 
    96911, 96912, 96913, 96914, 96915, 
    96916, 96917, 96918, 96919, 96920, 
    96921, 96922, 96923, 96924, 96925, 
    96926, 96927, 96928, 96929, 96930, 
    96931, 96932, 96933, 96934, 96935, 
    96936, 96937, 96938, 96939, 96940, 
    96941, 96942, 96943, 96944, 96945, 
    96946, 96947, 96948, 96949, 96950, 
    96951, 96952
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00089

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.62"
    },
    "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": 48,
      "rows_produced_per_join": 48,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "16.82",
        "eval_cost": "4.80",
        "prefix_cost": "21.62",
        "data_read_per_join": "183K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (96905,96906,96907,96908,96909,96910,96911,96912,96913,96914,96915,96916,96917,96918,96919,96920,96921,96922,96923,96924,96925,96926,96927,96928,96929,96930,96931,96932,96933,96934,96935,96936,96937,96938,96939,96940,96941,96942,96943,96944,96945,96946,96947,96948,96949,96950,96951,96952)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
96905
96906
96907
96908
96909
96910
96911
96912
96913
96914
96915
96916
96917
96918
96919
96920
96921
96922
96923
96924
96925
96926
96927
96928
96929
96930
96931
96932
96933
96934
96935
96936
96937
96938
96939
96940
96941
96942
96943
96944
96945
96946
96947
96948
96949
96950
96951
96952