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, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (4, 1, 8, 9, 10) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "12.01"
    },
    "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": 5,
      "rows_produced_per_join": 5,
      "filtered": "100.00",
      "index_condition": "((`danishecarter_latest`.`cscart_product_descriptions`.`product_id` in (4,1,8,9,10)) and (`danishecarter_latest`.`cscart_product_descriptions`.`lang_code` = 'en'))",
      "cost_info": {
        "read_cost": "11.01",
        "eval_cost": "1.00",
        "prefix_cost": "12.01",
        "data_read_per_join": "22K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description",
        "unit_name"
      ]
    }
  }
}

Result

product_id short_description full_description unit_name
1 <p> For the ultimate TV enthusiasts, incredible picture quality and advanced connectivity are just the first step; the Samsung UN65D8000 LED TV goes a step beyond, adding elegant design to the formula. On the commanding 65-inch screen you can enjoy Samsung' Smart TV, which puts the web, a wide range of apps, Skype video calling, and plenty more at your fingertips. Or connect a Blu-ray 3D player to get immersed in cinema-quality 3D programming--two pairs of active glasses are included. </p>
4 <p> Clear Motion Rate (CMR) is Samsung's more comprehensive and accurate measure for how well an LCD or LED TV can display fast-moving images. Previously, motion clarity was expressed simply by the refresh rate, measured in Hz. CMR, however, takes into account all three factors that contribute to motion clarity: panel refresh rate, image processor speed and backlight technology. </p>
8 <p> Although its attractive features, design, and passive 3D have merit, the picture quality issues of the Toshiba TL515U LED-based LCD TV lessen its appeal in the face of the stiff competition. </p>
9 <p>Although its attractive features, design, and passive 3D have merit, the picture quality issues of the Toshiba TL515U LED-based LCD TV lessen its appeal in the face of the stiff competition.</p>
10 <p>Although its attractive features, design, and passive 3D have merit, the picture quality issues of the Toshiba TL515U LED-based LCD TV lessen its appeal in the face of the stiff competition.</p>