Yes it's safe. Just make sure you dfidnt install roms or rooted your phone.

Is locking bootloader dangerous?

If your Android phone has a standard locked bootloader when a thief gets their hands on it, they won't be able to access the device's data without knowing its PIN or password. ... This would ensure your data is stored in an encrypted form, so people wouldn't be able to access your data without your encryption passphrase.

What happens if I relock bootloader?

Bootloader is a bit of code that tells your device's operating system how to boot up. ... Re-locking a bootloader will ensure that the device will only boot to Motorola signed and provided Android Images.