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 (
    92337, 92338, 92339, 92340, 88093, 84704, 
    84707, 91054, 90824, 90825, 89173, 
    91839, 87232, 87233, 87237, 87238, 
    87242, 87243, 87247, 87248, 88509, 
    88513, 88950, 88951
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00085

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "10.82"
    },
    "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": 24,
      "rows_produced_per_join": 24,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "8.42",
        "eval_cost": "2.40",
        "prefix_cost": "10.82",
        "data_read_per_join": "91K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (92337,92338,92339,92340,88093,84704,84707,91054,90824,90825,89173,91839,87232,87233,87237,87238,87242,87243,87247,87248,88509,88513,88950,88951)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
84704 Classique Components Fireclay Classic Basin 1 Tap Hole, 800mm - White
84707 Classique Components Fireclay Classic Basin 3 Tap Hole, 800mm - White
87232 Old London Straight Bath Front Panel 1700mm - Storm Grey
87233 Old London Straight Bath Front Panel 1800mm - Storm Grey
87237 Old London Straight Bath Front Panel 1700mm - Twilight Blue
87238 Old London Straight Bath Front Panel 1800mm - Twilight Blue
87242 Old London Straight Bath Front Panel 1700mm - Timeless Sand
87243 Old London Straight Bath Front Panel 1800mm - Timeless Sand
87247 Old London Straight Bath Front Panel 1700mm - Hunter Green
87248 Old London Straight Bath Front Panel 1800mm - Hunter Green
88093 Old London Richmond Washstand - Chrome
88509 Furniture Minimalist Slimline Ceramic Basin 1 Tap Hole 1000mm
88513 Furniture Mid-Edge Ceramic Basin 1 Tap Hole 1000mm
88950 Hudson Reed Fusion Straight Polymarble Basin - Compact 1000mm
88951 Hudson Reed Fusion Straight Polymarble Basin - Compact 1100mm
89173 nuie Ceramics Accessories Standard Wall Frame
90824 Nuie Back To Wall Corner Bath Panel - Left Hand
90825 Nuie Crescent Back To Wall Corner Bath Panel - Right Hand
91054 800 Classic Basin (840x472x185) 0TH
91839 BC Designs Plinth Only For 1800mm Acrylic Boat Bath - White
92337 BC Designs Victrion 3 Tier Towel Rack - Brushed Chrome
92338 BC Designs Victrion 3 Tier Towel Rack - Brushed Copper
92339 BC Designs Victrion 3 Tier Towel Rack - Brushed Gold
92340 BC Designs Victrion 3 Tier Towel Rack - Brushed Nickel