How is T3 immigration in the mornings? My flight's STA is 5:25 am (AY from HEL). What would your best estimate be from gate to the metro (no bags)?

I would leave on a 10:20 am, flight (AY to HEL), with no bags to check in and a boarding pass in hand. How much time would I need at the airport for immigration and security? Also, I hear there is a security check at the metro station before you can enter the platform. Will this take a lot of time at New Delhi Railway Station?

Thanks!