How can I add time to Time stype in sqlite?

I want to query a range less or more than 5 seconds from the time I chose. Currently, I tried this:

SELECT * FROM calendars where date = '2015-08-03' and stime >= time('time I chose','-6 second') and stime <= time('time I chose','+6 second')

but no success, please show me how to do that!