As OldFred's post states, you need to use an actual secure erase utility, such as the
The reason this will run so quickly is because the drive's contents are already transparently encrypted. That is, if you were to read the flash chips directly, you would not find any of the content you see on your drive when accessing it normally. The onboard controller handles this process completely transparently, storing the encryption key in a secure enclave within the controller.
This is useful both from a security and longevity standpoint. Encrypting data helps soften repetitive pattern writes from being so repetitive, which in turn helps to decrease the wear and tear on flash cells.
When you run a secure erase on an SSD, no data is actually being erased -- instead, the controller is generating a new encryption key and writing it into the secure enclave, overwriting the old key in the process and permanently rendering all binary data on the flash cells unrecoverable.