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 (
    85492, 85342, 85344, 85325, 85326, 85422, 
    85423, 85473, 85474, 85524, 85525, 
    86512, 86788, 86127, 86128, 86150, 
    86151, 83063, 83064, 83616, 83617, 
    85339, 89806, 89858
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00063

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 (85492,85342,85344,85325,85326,85422,85423,85473,85474,85524,85525,86512,86788,86127,86128,86150,86151,83063,83064,83616,83617,85339,89806,89858)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
83063 nuie Arno 800mm Wall Hung 1-Drawer Vanity & Thin-Edge Basin - Satin Green
83064 nuie Arno 800mm Wall Hung 1-Drawer Vanity & Curved Basin - Satin Green
83616 nuie Athena Wall Hung Single Drawer Vanity With Thin-Edge 1 Tap Hole Ceramic Basin 800mm - Gloss Grey
83617 nuie Athena Wall Hung Single Drawer Vanity With Curved 1 Tap Hole Ceramic Basin 800mm - Gloss Grey
85325 nuie Deco 800mm Wall Hung Single Drawer Vanity & Thin-Edge Basin - Satin Anthracite
85326 nuie Deco 800mm Wall Hung Single Drawer Vanity & Curved Basin - Satin Anthracite
85339 nuie Deco 600mm Wall Hung 2-Drawer Vanity & Mid-Edge Basin - Satin White
85342 nuie Deco 600mm Wall Hung 2-Drawer Vanity & Thin-Edge Basin - Satin White
85344 nuie Deco 600mm Wall Hung 2-Drawer Vanity & Curved Basin - Satin White
85422 nuie Deco 800mm Wall Hung Single Drawer Vanity & Thin-Edge Basin - Satin Grey
85423 nuie Deco 800mm Wall Hung Single Drawer Vanity & Curved Basin - Satin Grey
85473 nuie Deco 800mm Wall Hung Single Drawer Vanity & Thin-Edge Basin - Satin Blue
85474 nuie Deco 800mm Wall Hung Single Drawer Vanity & Curved Basin - Satin Blue
85492 nuie Deco 600mm Wall Hung 2-Drawer Vanity & Mid-Edge Basin - Satin Green
85524 nuie Deco 800mm Wall Hung Single Drawer Vanity & Thin-Edge Basin - Satin Green
85525 nuie Deco 800mm Wall Hung Single Drawer Vanity & Curved Basin - Satin Green
86127 Hudson Reed Havana Wall Hung 2 Drawer Vanity Basin Unit & Mid-Edge Ceramic Basin, 500mm - Graphite Grey
86128 Hudson Reed Havana Wall Hung 2 Drawer Vanity Basin Unit & Minimalist Ceramic Basin, 500mm - Graphite Grey
86150 Hudson Reed Havana Wall Hung 2 Drawer Vanity Basin Unit & Mid-Edge Ceramic Basin, 500mm - Coastal Grey
86151 Hudson Reed Havana Wall Hung 2 Drawer Vanity Basin Unit & Minimalist Ceramic Basin, 500mm - Coastal Grey
86512 Hudson Reed Juno 800mm Wall Hung Single Drawer Vanity & Mid-Edge 1 Tap Hole Basin - Autumn Oak
86788 Hudson Reed Juno Wall Hung 1 Drawer Vanity Basin Unit & Mid-Edge Ceramic Basin, 800mm - Metallic Slate
89806 Hudson Reed Urban Wall Hung 2 Drawer Vanity Unit with Minimalist Basin 600mm - Satin Grey
89858 Hudson Reed Urban Wall Hung 2 Drawer Vanity Unit with Minimalist Basin 600mm - Satin Blue