Where in civicrm_settings table is resource_url saved? I cannot use the System Settings/Resource URLs to set it, but can access the database.
Instead of editing the database why not just override the value in the civicrm.settings.php file?
Check you have
Then add $civicrm_setting['URL Preferences']['userFrameworkResourceURL'] = 'http://example.com/example-resource-url/';
More information here on this https://docs.civicrm.org/sysadmin/en/latest/customize/settings/
If you do want to update this directly in the database try the civicrm_setting table you want to search for a name of "userFrameworkResourceURL" and update the value column.
Best to make a back up of the database - or at the very least the table before changing it.
Alternatively you might also be able to set this via the api:
cv api Setting.create userFrameworkResourceURL="resource url here"
drush cvapi Setting.create userFrameworkResourceURL="resource url here"
depending on how broken your install is. Perhaps use Setting.get on dmaster via the api explorer to confirm what the appropriate format is: