You can change corresponding db/prefix/user/pass values in plugins/mobile/terawurfl.php (but note that plugin files will be overwritten on each MJ update):
TeraWurflConfig::$TABLE_PREFIX = $config->getValue('dbprefix').'TeraWurfl';
TeraWurflConfig::$DB_HOST = $host;
TeraWurflConfig::$DB_USER = $config->getValue('user');
TeraWurflConfig::$DB_PASS = $config->getValue('password');
TeraWurflConfig::$DB_SCHEMA = $config->getValue('db');
