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 (
    93908, 93909, 93910, 93911, 93912, 93913, 
    93914, 93915, 93916, 93917, 93918, 
    93919, 93920, 93921, 93922, 93923, 
    93924, 93925, 93926, 93927, 93928, 
    93929, 93930, 93931
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00082

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "10.82"
    },
    "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": 24,
      "rows_produced_per_join": 24,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "8.42",
        "eval_cost": "2.40",
        "prefix_cost": "10.82",
        "data_read_per_join": "91K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (93908,93909,93910,93911,93912,93913,93914,93915,93916,93917,93918,93919,93920,93921,93922,93923,93924,93925,93926,93927,93928,93929,93930,93931)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
93908
93909
93910
93911
93912
93913
93914
93915
93916
93917
93918
93919
93920
93921
93922
93923
93924
93925
93926
93927
93928
93929
93930
93931