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 (
    85717, 87551, 88404, 87460, 88500, 89453, 
    89466, 89474, 89482, 85681, 89458, 
    85728, 85745, 85755, 85765, 87463, 
    87550, 88497, 85735, 84773, 84786, 
    84795, 88199, 88211, 84777, 88196, 
    88208, 88498, 85725, 85742, 85752, 
    85762, 85732, 87513, 87529, 88451, 
    88468, 88484, 87462, 88173, 88221, 
    85671, 85691, 85703, 85715, 85679, 
    88496, 87516
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00098

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 (85717,87551,88404,87460,88500,89453,89466,89474,89482,85681,89458,85728,85745,85755,85765,87463,87550,88497,85735,84773,84786,84795,88199,88211,84777,88196,88208,88498,85725,85742,85752,85762,85732,87513,87529,88451,88468,88484,87462,88173,88221,85671,85691,85703,85715,85679,88496,87516)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}