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 (
    388949, 388817, 388776, 388620, 389157, 
    389807, 388552, 388758, 388618, 390227, 
    390278, 415512, 388798, 415708, 389151, 
    435299, 389464, 390285, 389281, 415534, 
    388567, 390150, 388837, 390206, 388522, 
    415625, 388434, 388449, 389069, 391767, 
    415532, 415734, 388711, 389064, 389015, 
    389041, 389372, 388428, 391732, 389258, 
    389533, 388671, 389603, 390289, 415624, 
    389566, 388947, 426893, 388486, 388871, 
    388397, 389560, 388617, 415520, 415732, 
    388997, 389442, 388830, 388795, 390292, 
    388972, 388784, 389044, 389456, 389221, 
    391730, 388702, 389063, 415535, 388887, 
    390225, 388840, 388592, 388888, 388931, 
    388652, 415466, 388437, 391722, 388627, 
    389508, 390171, 388850, 389094, 390152, 
    389246, 389329, 389824, 388690, 388937, 
    389223, 388744, 389083, 389364, 389857, 
    390214, 389232, 390139, 415509, 388689
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00314

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "140.18"
    },
    "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": 100,
      "rows_produced_per_join": 100,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "120.18",
        "eval_cost": "20.00",
        "prefix_cost": "140.18",
        "data_read_per_join": "682K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`webmarco`.`cscart_product_descriptions`.`product_id` in (388949,388817,388776,388620,389157,389807,388552,388758,388618,390227,390278,415512,388798,415708,389151,435299,389464,390285,389281,415534,388567,390150,388837,390206,388522,415625,388434,388449,389069,391767,415532,415734,388711,389064,389015,389041,389372,388428,391732,389258,389533,388671,389603,390289,415624,389566,388947,426893,388486,388871,388397,389560,388617,415520,415732,388997,389442,388830,388795,390292,388972,388784,389044,389456,389221,391730,388702,389063,415535,388887,390225,388840,388592,388888,388931,388652,415466,388437,391722,388627,389508,390171,388850,389094,390152,389246,389329,389824,388690,388937,389223,388744,389083,389364,389857,390214,389232,390139,415509,388689)) and (`webmarco`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}