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 (
    88984, 88234, 88238, 90837, 89843, 89895, 
    89968, 85733, 85670, 85690, 85702, 
    85714, 85678, 87517, 87533, 88567, 
    88568, 89842, 89894, 89967, 89791, 
    85669, 85689, 85701, 85713, 85730, 
    85747, 85757, 85767, 85677, 85737, 
    89455, 89468, 89476, 89484, 89790, 
    89460, 88175, 88223, 84774, 84787, 
    84796, 88172, 88220, 84778, 85673, 
    85693, 85705
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00095

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 (88984,88234,88238,90837,89843,89895,89968,85733,85670,85690,85702,85714,85678,87517,87533,88567,88568,89842,89894,89967,89791,85669,85689,85701,85713,85730,85747,85757,85767,85677,85737,89455,89468,89476,89484,89790,89460,88175,88223,84774,84787,84796,88172,88220,84778,85673,85693,85705)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}