hello, wait 41942 seconds and it will solved self :D - just a joke :p
did u try first after edit config, reload plugin? if yes - maybe it will store in the oxide/data something like boatlicence_cooldown?! if yes - unload BoatLicence, if there are something like this data, delete it and reload plugin BoatLicence again.
I dont use this plugin its just a suppose.
oxide/data doesn't show remain time, but I have solve it setting chat command to spawn a boat at 0