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 (
    96881, 96882, 96883, 96884, 96885, 96886, 
    96887, 96888, 96889, 96890, 96891, 
    96892, 96893, 96894, 96895, 96896, 
    96897, 96898, 96899, 96900, 96901, 
    96902, 96903, 96904, 96905, 96906, 
    96907, 96908, 96909, 96910, 96911, 
    96912, 96913, 96914, 96915, 96916, 
    96920, 96921, 96922, 96923, 96924, 
    96925, 96926, 96927, 96928, 96929, 
    96930, 96931
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00084

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 (96881,96882,96883,96884,96885,96886,96887,96888,96889,96890,96891,96892,96893,96894,96895,96896,96897,96898,96899,96900,96901,96902,96903,96904,96905,96906,96907,96908,96909,96910,96911,96912,96913,96914,96915,96916,96920,96921,96922,96923,96924,96925,96926,96927,96928,96929,96930,96931)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
96881
96882
96883
96884
96885
96886
96887
96888
96889
96890
96891
96892
96893
96894
96895
96896
96897
96898
96899
96900
96901
96902
96903
96904
96905
96906
96907
96908
96909
96910
96911
96912
96913
96914
96915
96916
96920
96921
96922
96923
96924
96925
96926
96927
96928
96929
96930
96931