Filter data hourly basis--how to construct Start Date Time & End Date Time

We have Modified on Date filed , which is Date Time.

Requirement is every hour scheduler runs and pick the data from now to past hour.

If the current date time is 26/12/2023 11:30 AM IST then Start Date Time =  26/12/2023 11:30 AM End Date Time  26/12/2023 10:30 AM.

Start Date Time I am calculating like =a!subtractDateTime(  startDateTime: now())

End Date Time: a!subtractDateTime(startDateTime: ac!startDateTime, hours: 1)

above 2 are giving me proper startDateTime and End Date Time. but when I pass to query Filter, I am using the <=Strat DateTime & >=End DateTime.

I have one record with Modified on is 26/12/2023 10:50 AM which is in between Start Date & End Date mentioned above. but still I am getting 0 Records from database.

How to construct Start  Time & End Date Time get hourly data.