You should never have to run this command manually. All keys are contained in their respective packages archlinux-keyring and manjaro-keyring.
This will reinstall the required packages and fix your issues (if they are keyring-related): [HowTo] Work around gpg verification issue on left behind systems
bash <(curl -s "https://notabug.org/megavolt/random-scripts/raw/master/fix-gpg-pacman.sh") --basic