Comparing time value with current time value using Now() function

On option is to break out the components and compare the date, current hour and current minutes as part of the output. So something like: 

var datetime fieldDT = [Your Field with Date/Time];

var timeofday fieldTOD = ToTimeOfDay($fieldDT);

var timeofday nowTOD = ToTimeOfDay(Now());

( ToDate($fieldDT) = ToDate(Now())) and

( Hour($fieldTOD) = Hour($nowTOD) ) and

( Minute($fieldTOD) = Minute($nowTOD) )