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 (
    88044, 87987, 90828, 87632, 88561, 87637, 
    90827, 87938, 87941, 87997, 88026, 
    87764, 87770, 87773, 87777, 87781, 
    87788, 87794, 87281, 87289, 87882, 
    87988, 88036, 88047, 88048, 86862, 
    90324, 90326, 88050, 88051
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00073

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "13.52"
    },
    "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": 30,
      "rows_produced_per_join": 30,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "10.52",
        "eval_cost": "3.00",
        "prefix_cost": "13.52",
        "data_read_per_join": "114K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (88044,87987,90828,87632,88561,87637,90827,87938,87941,87997,88026,87764,87770,87773,87777,87781,87788,87794,87281,87289,87882,87988,88036,88047,88048,86862,90324,90326,88050,88051)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
86862 nuie Deco 800mm Laminate Worktop - Bellato Grey
87281 nuie Deco 600mm Laminate Worktop - Black Sparkle
87289 nuie Deco 600mm Laminate Worktop - White Sparkle
87632 nuie Merit Wall Hung 1 Door Vanity Unit 500mm - Gloss White
87637 nuie Merit Wall Hung 1 Door Vanity Unit - Slimline 500mm - Anthracite Woodgrain
87764 Hudson Reed Juno 1200mm Worktop - Autumn Oak
87770 Hudson Reed Juno 1200mm Worktop - Graphite Grey
87773 Hudson Reed Juno 1200mm Worktop - Coastal Grey
87777 nuie Arno 1200mm Worktop - Solace Oak
87781 Juno Components Colour Match Worktop (605mm x 390mm x 18mm), 1200mm - Metallic Slate
87788 nuie Arno 1200mm Worktop - Anthracite
87794 nuie Arno 1200mm Worktop - Charcoal Black
87882 nuie Mayford Square Ceramic 1 Tap Hole Basin 650mm
87938 Hudson Reed Chancery Large Basin 1 Tap Hole
87941 Hudson Reed Chancery Large Basin 2 Tap Hole
87987 nuie Bliss Square Cistern & Fittings
87988 nuie Bliss Square 600mm Basin 1 Tap Hole
87997 nuie Provost Cistern
88026 nuie Ivo Close Coupled Cistern
88036 Old London Richmond Corner Basin 421 x 421 x 595mm
88044 Old London Richmond High/Low Level Pan (Excluding Seat)
88047 nuie Carlton High Level Cistern (Including Fittings)
88048 Old London Richmond High Level Cistern B (Including Fittings)
88050 nuie Carlton Toilet Cistern with Chrome Lever & Fitting
88051 Old London Richmond Toilet Cistern B Ceramic Lever Fittings
88561 Hudson Reed Fusion Wall Hung 1 Door Vanity Unit - Compact 400mm - Gloss White
90324 nuie Ceramics Accessories Pneumatic Dual Flush Universal Access Concealed Cistern - Matt Black
90326 nuie Ceramics Accessories Pneumatic Dual Flush Universal Access Concealed Cistern - Matt White
90827 Nuie Core 500mm Thin Edge Basin 1TH
90828 Nuie Core 600mm Thin Edge Basin 1TH