Hi
@hriannyi,
Google pay could be enable by default to allow locked screen payments only for a certain amount of payments and for a limited amount of locked transaction. You can check on Google Pay help for further details on this.
For added security, you can set up your phone so that it must be unlocked to complete an NFC transaction.
To turn on this setting on Google pay app:
Go to Settings
Tap Connected devices
Connection preferences
NFC.
Turn on Require device unlock for NFC.