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 (
    83988, 83989, 84111, 90087, 90097, 88930, 
    90107, 91837, 92011, 92012, 92013, 
    92014, 92015, 92016, 92017, 92099, 
    92100, 92101, 92102, 92103, 92104, 
    92105, 83089, 84096, 83104, 84110, 
    90080, 83092, 92500, 84099, 86219, 
    89526, 89723, 90064, 89641, 91298, 
    83106, 91305, 84112, 89488, 89637, 
    92066, 92082, 83109, 83119, 85039, 
    91306, 91299
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00101

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 (83988,83989,84111,90087,90097,88930,90107,91837,92011,92012,92013,92014,92015,92016,92017,92099,92100,92101,92102,92103,92104,92105,83089,84096,83104,84110,90080,83092,92500,84099,86219,89526,89723,90064,89641,91298,83106,91305,84112,89488,89637,92066,92082,83109,83119,85039,91306,91299)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
83089 nuie Arvan Wall Mounted Thermostatic Bath Shower Mixer - Chrome
83092 nuie Arvan Deck Mounted Bath Shower Mixer With Kit - Chrome
83104 nuie Arvan Deck Mounted 4 Tap Hole Bath Shower Mixer No Spout - Chrome
83106 nuie Arvan Wall Mounted 3 Tap Hole Basin Mixer With Plate - Chrome
83109 nuie Arvan Deck Mounted Bath Filler - Matt Black
83119 nuie Arvan Deck Mounted Bath Filler - Gunmetal
83988 Old London White Topaz With Lever Handle 3 Tap Hole Wall Mounted Basin Mixer - Chrome
83989 Old London White Topaz With Crosshead Handle 3 Tap Hole Wall Mounted Basin Mixer - Chrome
84096 nuie Binsey Wall Mounted Thermostatic Bath Shower Mixer - Chrome
84099 nuie Binsey Deck Mounted Bath Shower Mixer With Kit - Chrome
84110 nuie Binsey Deck Mounted 4 Tap Hole Bath Shower Mixer No Spout - Chrome
84111 nuie Binsey Deck Mounted 3 Tap Hole Basin Mixer With Pop Up Waste - Chrome
84112 nuie Binsey Wall Mounted 3 Tap Hole Basin Mixer With Plate - Chrome
85039 Standpipes 660mmx40mm Freestanding Legs
86219 nuie Hardy Bath Filler - Chrome
88930 Hudson Reed Tec Single Lever Wall Mounted Basin Bath Filler - Chrome
89488 Hudson Reed Soar Wall Plated Single Lever Basin Mixer - Chrome
89526 Hudson Reed Sottile Wall Plated Single Lever Basin Mixer - Chrome
89637 Hudson Reed Tec Crosshead Mono Basin Mixer - Brushed Brass
89641 Hudson Reed Revolution Mono Basin Mixer - Chrome
89723 nuie Vibe Bath Filler - Chrome
90064 Hudson Reed Willow Wall Plated Single Lever Basin Mixer - Chrome
90080 nuie Windon Wall Mounted 2 Tap Hole Basin Mixer With Plate - Chrome
90087 nuie Windon Deck Mounted Bath Filler - Matt Black
90097 nuie Windon Deck Mounted Bath Filler - Gunmetal
90107 nuie Windon Mono Basin Mixer With Push Button Waste - Brushed Brass
91298 nuie Aztec Deck Mount 3 Tap Hole Basin Mixer - Chrome
91299 nuie Aztec Deck Mount Bath Filler - Chrome
91305 nuie Aztec Deck Mount Mono Basin Mixer Tap with Push Button Waste - Brushed Brass
91306 nuie Aztec Wall Mount 3 Tap Hole Basin Mixer - Brushed Brass
91837 BC Designs Plinth Only For 1580mm Acrylic Boat Bath - White
92011 BC Designs Victrion Deck Mounted Crosshead Bath Pillar Taps - Brushed Chrome
92012 BC Designs Victrion Deck Mounted Crosshead Bath Pillar Taps - Brushed Copper
92013 BC Designs Victrion Deck Mounted Crosshead Bath Pillar Taps - Brushed Gold
92014 BC Designs Victrion Deck Mounted Crosshead Bath Pillar Taps - Brushed Nickel
92015 BC Designs Victrion Deck Mounted Crosshead Bath Pillar Taps - Copper
92016 BC Designs Victrion Deck Mounted Crosshead Bath Pillar Taps - Gold
92017 BC Designs Victrion Deck Mounted Crosshead Bath Pillar Taps - Nickel
92066 BC Designs Victrion Deck Mounted Lever Mono Bidet Mixer Tap - Chrome
92082 BC Designs Victrion Deck Mounted Crosshead Mono Bidet Mixer Tap - Chrome
92099 BC Designs Victrion Deck Mounted Lever Bath Pillar Taps - Brushed Chrome
92100 BC Designs Victrion Deck Mounted Lever Bath Pillar Taps - Brushed Copper
92101 BC Designs Victrion Deck Mounted Lever Bath Pillar Taps - Brushed Gold
92102 BC Designs Victrion Deck Mounted Lever Bath Pillar Taps - Brushed Nickel
92103 BC Designs Victrion Deck Mounted Lever Bath Pillar Taps - Copper
92104 BC Designs Victrion Deck Mounted Lever Bath Pillar Taps - Gold
92105 BC Designs Victrion Deck Mounted Lever Bath Pillar Taps - Nickel
92500 BC Designs Extended Bath Filler - Chrome