For example after refreshing of Sandbox - I need to know that first version of Sandbox is not longer exists.
In such case any REST request return 401 (like when session id is expired) when any SOAP (I tested only a few) return INSUFFICIENT_ACCESS: Inactive Organization.
Also I know that it is possible to query SandboxInfo and SandboxProcess of Prod instance.
Last way - parse a html for string 'Your organization has been disabled'.
Maybe exists some other way? Is it possible to execute some api-call from Sandbox to get status?