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 (
    85580, 86863, 92151, 92152, 92153, 92353, 
    92354, 92355, 92356, 91893, 91894, 
    91895, 92337, 92338, 92339, 92340, 
    91839, 92450, 92451, 92452, 92453, 
    92454, 92455, 92456, 91838, 91837, 
    92500, 85039, 87370, 89609, 89610, 
    92173, 92174, 92395, 92396, 92397, 
    92398, 92399, 92198, 92199, 92200, 
    92201, 92202, 92444, 92445, 92446, 
    92447, 92146
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00106

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.63"
    },
    "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": 48,
      "rows_produced_per_join": 48,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "16.83",
        "eval_cost": "4.80",
        "prefix_cost": "21.63",
        "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 (85580,86863,92151,92152,92153,92353,92354,92355,92356,91893,91894,91895,92337,92338,92339,92340,91839,92450,92451,92452,92453,92454,92455,92456,91838,91837,92500,85039,87370,89609,89610,92173,92174,92395,92396,92397,92398,92399,92198,92199,92200,92201,92202,92444,92445,92446,92447,92146)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
85039 Standpipes 660mmx40mm Freestanding Legs
85580 Roll Top Bath Pack
86863 1/2 Shower Curtain Ring
87370 Old London Deacon Leg Leg Set M1 For Traditional Freestanding Baths Deacon - Chrome
89609 Old London Corbel Leg Set C For Traditional Freestanding Baths - Chrome
89610 Old London Pride Leg Set C2 For Traditional Freestanding Baths - Chrome
91837 BC Designs Plinth Only For 1580mm Acrylic Boat Bath - White
91838 BC Designs Plinth Only For 1700mm Acrylic Boat Bath - White
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
92146 BC Designs Standpipes Traditional Cast Freestanding Bath Legs - 660mm x 40mm - Chrome
92151 BC Designs Standpipes Traditional Bath Legs with Adjustable Shrouds - Copper
92152 BC Designs Standpipes Traditional Bath Legs with Adjustable Shrouds - Gold
92153 BC Designs Standpipes Traditional Bath Legs with Adjustable Shrouds - Nickel
92173 BC Designs Flushpipe Mid Height Toilet Flush Pipe Only - Gold
92174 BC Designs Flushpipe Mid Height Toilet Flush Pipe Only - Nickel
92198 BC Designs Bath Wastes Push Down Concealed Bath Waste - Brushed Chrome
92199 BC Designs Bath Wastes Push Down Concealed Bath Waste - Brushed Gold
92200 BC Designs Bath Wastes Push Down Concealed Bath Waste - Brushed Nickel
92201 BC Designs Bath Wastes Push Down Concealed Bath Waste - Gold
92202 BC Designs Bath Wastes Push Down Concealed Bath Waste - 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
92353 BC Designs Bath Legs with Adjustable Shrouds - Brushed Chrome
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
92395 BC Designs Victrion Mid Height Flush Pipe Only - Brushed Chrome
92396 BC Designs Victrion Mid Height Flush Pipe Only - Brushed Copper
92397 BC Designs Victrion Mid Height Flush Pipe Only - Brushed Gold
92398 BC Designs Victrion Mid Height Flush Pipe Only - Brushed Nickel
92399 BC Designs Victrion Mid Height Flush Pipe Only - Copper
92444 BC Designs Push Down Concealed Bath Waste - Brushed Copper
92445 BC Designs Push Down Concealed Bath Waste - Black Silk
92446 BC Designs Push Down Concealed Bath Waste - Copper
92447 BC Designs Push Down Concealed Bath Waste - White
92450 BC Designs Push Down Freestanding Bath Waste - Brushed Chrome
92451 BC Designs Push Down Freestanding Bath Waste - Brushed Copper
92452 BC Designs Push Down Freestanding Bath Waste - Brushed Gold
92453 BC Designs Push Down Freestanding Bath Waste - Brushed Nickel
92454 BC Designs Push Down Freestanding Bath Waste - Copper
92455 BC Designs Push Down Freestanding Bath Waste - Gold
92456 BC Designs Push Down Freestanding Bath Waste - Nickel
92500 BC Designs Extended Bath Filler - Chrome