Truncating SYSDATE gives you 12:00 AM on the current date.
TRUNC(SYSDATE)

Adding 1 puts the date at midnight tonight for the current date.
+1

Adding this causes date date to be 1 minute later
+(1/24*60)

The final function would be as follows.
TRUNC(SYSDATE) + 1 + (1/24*60)