Grant execute on all users does not work as the manual says

I have a stored procedure that I want all my users to be able to execute, without having to assign the privilege individually, since they are hundreds.
So I found in the manual this statement
GRANT EXECUTE ON PROCEDURE MariaDBProc TO '*'@'localhost';
http://www.techonthenet.com/mariadb/grant_revoke.php
In old mysql, they say to use
GRANT EXECUTE ON PROCEDURE MariaDBProc TO ''@'localhost';
I actually use
GRANT EXECUTE ON PROCEDURE MariaDBProc TO '*'@'%';
or
GRANT EXECUTE ON PROCEDURE MariaDBProc TO ''@'';
but neither statement makes my users to execute the stored procedure.