You can set some Sybase variables to see the Query Plan such as the following:

set showplan  on
set statistics io on
set statistics time on
exec my_proc (my_arg1, my_arg2, ...)
go

I have put this into a shell script to pass the command line arguments including stored procedure name and parameters.

isql  -Uxxx   -Pyyy   <<-_EOF_
set showplan  on
set statistics io on
set statistics time on
exec $*
go
_EOF_

You use this to see if there are any table scans which should be avoided at all costs.

Good SQL, good night.