Check whether moto g 2nd gen refurbished or not
You can contact your wireless carrier and give them the IMEI.  They'd able to tell you if it's been activated on their network before, at least.

You can also contact Motorola to check on the status of the warranty and whether or not the phone has ever been sent back to them for service, etc.

The IMEI is the "International Mobile Station Equipment Identity" - a number you can usually find in the "About Phone" section of a phone's settings.  On your phone I think it would be Settings > About Phone > Status.