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 (
    87276, 87275, 87274, 87269, 88526, 88759, 
    87187, 87204, 87221, 87229, 84767, 
    84780, 84789, 84762, 88556, 88557, 
    88664, 88711, 88396, 88525, 88524, 
    88555, 93749, 93830
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00070

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 (87276,87275,87274,87269,88526,88759,87187,87204,87221,87229,84767,84780,84789,84762,88556,88557,88664,88711,88396,88525,88524,88555,93749,93830)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
84762 nuie Classique Wall Hung 2 Door Mirror Cabinet, 600mm - Satin White
84767 nuie Classique Wall Hung 2 Door Mirror Cabinet, 600mm - Satin Anthracite
84780 nuie Classique Wall Hung 2 Door Mirror Cabinet, 600mm - Satin Grey
84789 nuie Classique Wall Hung 2 Door Mirror Cabinet, 600mm - Satin Green
87187 Old London Wall Hung Flat Mirror 600mm - Storm Grey
87204 Old London Wall Hung Flat Mirror 600mm - Twilight Blue
87221 Old London Wall Hung Flat Mirror 600mm - Timeless Sand
87229 Old London Wall Hung Flat Mirror 600mm - Hunter Green
87269 nuie Lynx 700mm x 500mm Ambient Mirror Touch Sensor
87274 Salana 600mm Round Touch Sensor Illuminated Mirror Touch Sensor- Black
87275 Salana 600mm Round Touch Sensor Illuminated Mirror Touch Sensor- Brushed Brass
87276 Salana 600mm Round Touch Sensor Illuminated Mirror Touch Sensor- Chrome
88396 nuie Mayford Wall Hung Corner Single Door Mirror Cabinet - Gloss White
88524 nuie Eden Wall Hung 2 Door Mirror Cabinet 600mm - Gloss White
88525 nuie Eden Wall Hung 3 Door Mirror Cabinet 900mm - Gloss White
88526 nuie Eden Wall Hung 4 Door Mirror Cabinet 1200mm - Gloss White
88555 Hudson Reed Fusion Fitted Wall Hung 1 Door Mirror Cabinet 450mm - Gloss White
88556 Hudson Reed Fusion Fitted Wall Hung 2 Door Mirror Unit (50/50) 600mm - Gloss White
88557 Hudson Reed Fusion Fitted Wall Hung 2 Door Mirror Unit (75/25) 600mm - Gloss White
88664 Hudson Reed Fusion Fitted Wall Hung 1 Door Mirror Cabinet 450mm - Anthracite Woodgrain
88711 Hudson Reed Fusion Fitted Wall Hung 1 Door Mirror Cabinet 450mm - Hacienda Black
88759 Hudson Reed Fusion Fitted Wall Hung 1 Door Mirror Cabinet 450mm - Gloss Grey
93749
93830