On MariaDB event scheduler doesn't run
First rule of  *nix admin is: Logs are your friends

Looking at logfile:

2020-05-15 14:41:00 1108 [ERROR] Event Scheduler: [phpmyadmin@localhost].[integrity.DELETE_EXPIRED_SESSIONS] execution failed, user no longer has EVENT privilege.
2020-05-15 14:41:00 1108 [ERROR] Event Scheduler: [phpmyadmin@localhost][integrity.DELETE_EXPIRED_SESSIONS] Access denied for user 'phpmyadmin@localhost' to database 'integrity'
2020-05-15 14:41:00 1108 [Note] Event Scheduler: [phpmyadmin@localhost].[integrity.DELETE_EXPIRED_SESSIONS] event execution failed.


The user defined at Definer: phpmyadmin@localhost MUST be an existing user and with all privileges to access your database...

Fixed that, everything worked fine.