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 (
    92354, 92355, 92356, 88953, 88954, 87879, 
    82403, 82410, 82424, 91893, 91894, 
    91895, 92337, 92338, 92339, 92340, 
    88093, 84704, 84707, 91054, 90824, 
    90825, 89173, 91839, 87232, 87233, 
    87237, 87238, 87242, 87243
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00100

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 (92354,92355,92356,88953,88954,87879,82403,82410,82424,91893,91894,91895,92337,92338,92339,92340,88093,84704,84707,91054,90824,90825,89173,91839,87232,87233,87237,87238,87242,87243)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
82403 nuie Shower Kits Slide Rail Kit - Matt Black
82410 nuie Shower Kits Square Slider Rail Kit with Elbow - Gunmetal
82424 nuie Shower Kits Slide Rail Kit - Brushed Brass
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
87879 nuie Mayford Round Ceramic 1 Tap Hole Basin 1200mm
88093 Old London Richmond Washstand - Chrome
88953 Hudson Reed Fusion Left Hand Square L-Shaped 1 Tap Hole Polymarble Basin 1000mm
88954 Hudson Reed Fusion Right Hand Square L-Shaped 1 Tap Hole Polymarble Basin 1000mm
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
91893 BC Designs Victrion 3 Tier Towel Rack - Copper
91894 BC Designs Victrion 3 Tier Towel Rack - Gold
91895 BC Designs Victrion 3 Tier Towel Rack - Nickel
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
92354 BC Designs Bath Legs with Adjustable Shrouds - Brushed Copper
92355 BC Designs Bath Legs with Adjustable Shrouds - Brushed Gold
92356 BC Designs Bath Legs with Adjustable Shrouds - Brushed Nickel