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 (
    88799, 88006, 88013, 88015, 87972, 88703, 
    88750, 87944, 88595, 88154, 87874, 
    87783, 87880, 87873, 88797, 87782, 
    88701, 88748, 88596, 88594, 92893, 
    92894, 93002, 93003
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00094

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "12.97"
    },
    "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": "10.57",
        "eval_cost": "2.40",
        "prefix_cost": "12.97",
        "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 (88799,88006,88013,88015,87972,88703,88750,87944,88595,88154,87874,87783,87880,87873,88797,87782,88701,88748,88596,88594,92893,92894,93002,93003)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
87782 Juno Components Colour Match Worktop (605mm x 390mm x 18mm), 600mm - Metallic Slate
87783 Juno Components Colour Match Worktop (605mm x 390mm x 18mm), 800mm - Metallic Slate
87873 nuie Mayford Round Ceramic 1 Tap Hole Basin 450mm
87874 nuie Mayford Round Ceramic 1 Tap Hole Basin 550mm
87880 nuie Mayford Square Ceramic 1 Tap Hole Basin 450mm
87944 nuie Asselby Small Cloakroom Basin 1 Tap Hole
87972 Nuie 545mm Basin 1 Tap Hole
88006 nuie Harmony 500mm Basin 1 Tap Hole
88013 nuie Melbourne Large Basin 1 Tap Hole
88015 nuie Melbourne Large Basin 2 Tap Hole
88154 nuie Lawton 560mm Basin 1 Tap Hole
88594 Hudson Reed Fusion Fitted Plinth 1250mm - Gloss White
88595 Hudson Reed Fusion Fitted Decorative End Panel - Gloss White
88596 Hudson Reed Fusion Fitted Plinth 2000mm - Gloss White
88701 Hudson Reed Fusion Fitted Plinth 1250mm - Anthracite Woodgrain
88703 Hudson Reed Fusion Fitted Plinth 2000mm - Anthracite Woodgrain
88748 Hudson Reed Fusion Fitted Plinth 1250mm - Hacienda Black
88750 Hudson Reed Fusion Fitted Plinth 2000mm - Hacienda Black
88797 Hudson Reed Fusion Fitted Plinth 1250mm - Gloss Grey
88799 Hudson Reed Fusion Fitted Plinth 2000mm - Gloss Grey
92893
92894
93002
93003