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 (
    190720, 190686, 190711, 190675, 190708, 
    190716, 190712, 190700, 190710, 190709, 
    190721, 190722, 190680, 190701, 190717, 
    190714, 190679, 190715, 190681, 190694, 
    190685, 190677, 190688, 190687, 190678, 
    190682, 190684, 190702, 190704, 190703, 
    190706, 190707
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00126

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "44.86"
    },
    "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": 32,
      "rows_produced_per_join": 32,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "38.46",
        "eval_cost": "6.40",
        "prefix_cost": "44.86",
        "data_read_per_join": "218K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`webmarco`.`cscart_product_descriptions`.`product_id` in (190720,190686,190711,190675,190708,190716,190712,190700,190710,190709,190721,190722,190680,190701,190717,190714,190679,190715,190681,190694,190685,190677,190688,190687,190678,190682,190684,190702,190704,190703,190706,190707)) and (`webmarco`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}