In prestashop 1.7 you will see cookie key in "app/config/parameters.php" instead of "config/settings.inc.php"
Assume that we have cookie key: "abc". We will reset password
123456 for admin "admin@ahihi.com" by SQL:
UPDATE ps_employee SET passwd = MD5('abc123456') WHERE email='admin@ahihi.com';
Then you can login to admin dashboard with account: admin@ahihi.com / 123456