ENCRYPT()
returns a binary string.
By default, MySQL Workbench does not display binary strings (to avoid accidental misinterpretation); however it is possible to display binary string values in output grids: View > Edit > Preferences > SQL Editor > Treat BINARY/VARBINARY
as nonbinary character string.
Alternatively, transcode the result to a non-binary string:
SELECT CONVERT(ENCRYPT('test') USING utf8)
Or encode it in a suitable fashion:
SELECT HEX(ENCRYPT('test'))