To reset the password for the admin account back to admin, change the hash to 21232F297A57A5A743894A0E4A801FC3.

UPDATE tusers
SET Password = '21232F297A57A5A743894A0E4A801FC3'
WHERE UserName = 'admin'

For Mura 6.2 the hash of admin is $2a$10$N8IpdikybLXU1UCR/B3bq./HjG.TCLLHgX0qmRAM5IGW2.HTCkRvG