If again you have problems with some pubkey not present, do this
mv /etc/pacman.d/gnupg /etc/pacman.d/gnupg.bkp
pacman-key --init
pacman-key --wpopulate
If again you have problems with some pubkey not present, do this
mv /etc/pacman.d/gnupg /etc/pacman.d/gnupg.bkp
pacman-key --init
pacman-key --wpopulate