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 (
    88078, 89985, 89986, 88041, 88055, 88085, 
    88071, 88076, 88072, 87960, 88030, 
    88019, 87992, 88001, 88005, 87939, 
    87989, 87943, 87973, 87999, 90808, 
    87965, 88014, 88020, 94485, 94492, 
    94510, 94574, 94579, 95757, 95759, 
    95773, 95777, 95827, 95828, 97609, 
    97616, 97634, 97698, 97703, 99113, 
    99117, 99131, 99135, 99144, 99165, 
    99168, 99174, 99176, 99179, 99193, 
    99198, 99199, 99208, 99219, 99233, 
    99249, 99250, 99254, 99256, 99263, 
    99275, 99279, 99345, 100674, 100675, 
    101682, 101683
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00061

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "30.63"
    },
    "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": 68,
      "rows_produced_per_join": 68,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "23.83",
        "eval_cost": "6.80",
        "prefix_cost": "30.63",
        "data_read_per_join": "259K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (88078,89985,89986,88041,88055,88085,88071,88076,88072,87960,88030,88019,87992,88001,88005,87939,87989,87943,87973,87999,90808,87965,88014,88020,94485,94492,94510,94574,94579,95757,95759,95773,95777,95827,95828,97609,97616,97634,97698,97703,99113,99117,99131,99135,99144,99165,99168,99174,99176,99179,99193,99198,99199,99208,99219,99233,99249,99250,99254,99256,99263,99275,99279,99345,100674,100675,101682,101683)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
87939 Hudson Reed Chancery Pedestal
87943 nuie Asselby Pedestal
87960 nuie Ambrose Full Pedestal
87965 nuie Freya Full Pedestal
87973 nuie Ava Full Pedestal
87989 nuie Bliss Square Pedestal
87992 nuie Bliss Semi Pedestal
87999 nuie Provost Round Pedestal
88001 nuie Provost Semi Pedestal
88005 nuie Harmony Pedestal
88014 nuie Melbourne Full Pedestal
88019 nuie Ivo Pedestal
88020 nuie Ivo Semi Pedestal
88030 nuie Legend Pedestal
88041 Old London Richmond Comfort Height Full Pedestal
88055 nuie Carlton Full Pedestal
88071 Hudson Reed Arlo Full Pedestal
88072 Hudson Reed Arlo Square Semi Pedestal
88076 Hudson Reed Maya Full Pedestal
88078 Hudson Reed Maya Semi Pedestal
88085 nuie Ambrose Semi Pedestal
89985 BC Designs Victrion Pedestal (640mm Basin) - White
89986 BC Designs Victrion Pedestal (540mm Basin) - White
90808 Nuie Lawton Full Pedestal - Gloss White
94485
94492
94510
94574
94579
95757
95759
95773
95777
95827
95828
97609
97616
97634
97698
97703
99113
99117
99131
99135
99144
99165
99168
99174
99176
99179
99193
99198
99199
99208
99219
99233
99249
99250
99254
99256
99263
99275
99279
99345
100674
100675
101682
101683