I just had the same exact issue on the same exact phone. After doing some digging it seems like this happens when Android has a problem optimizing one or more apps, so it stubbornly retries all of them. So I uninstalled apps one-by-one and rebooted, and the problem went away after uninstalling SuperSU.
Not wanting to leave my phone unrooted, I noticed I had installed the latest SuperSU (2.79 SR3), so I went here and downloaded the latest stable release (2.79):
After installing it I no longer had any issues.
During my troubleshooting I also cleared the cache, although I'm not sure if it helped or not:
Boot to recovery
For the Moto G 1st generation:
Power off the phone
Press and hold volume down button, press and hold power button, wait for about 4 seconds and then release both buttons
Press volume down to select Recovery and press volume up to boot to recovery
Clear the cache
For the Moto G 1st generation (stock recovery):
If you get to a screen that says "No command"
- Press and hold the power button for 2-3 seconds
- Without releasing power button, press volume up button and release the volume up button
- Release the power button
Use the volume buttons to move down to wipe cache partition and select it with the power button
Wait for it to finish (it can take a while) then reboot