Logic problem - UTC dateTime comparison

I have these records in my table:

11/11/2015 04:48:05 pm

11/11/2015 04:50:58 pm

11/11/2015 05:07:17 pm

11/11/2015 05:08:32 pm 

When i use my DateTimeUtil::getSystemDateTime(); - todays time

i need to compare the other records with todays time, to find the record which is closest to the current datetime.

I am thinking of using DateTimeUtil::getDifference but i can't make the logic right when there are more then two UTC dateTime.