Moto e 1st Gen Reboots while booting.

I unlocked and rooted my moto e 1st Gen mobile. Intially it was fine. But after few days when forgot to charge it, it switched off. Then when i tried to charge it, the phone keeps on rebooting. It means it reboots in the middle of booting. what should i do now?
How to hard shutdown the phone? or How to get to boot menu? Thanks in advance