The following query uses the status bits in master..syslogins to identify locked logins

select name from master..syslogins where status&2=2
go

The various status bits in syslogins correspond to the below, to find them in syslogins simply substitute 2 above with the relevant number:

2 – Account is locked.
4 – Password has expired. This is set on the user’s first login attempt after expiration.
8 – Indicates that the value of exempt inactive lock is set to TRUE. It is not applicable for login profile rows.
16 – OMNI:autoconnect mode is enabled.
32 – May use SAP ASE internal authentication mechanism – syslogins.
64 – May use LDAP external authentication.
128 – May use PAM external authentication.
256 – May use Kerberos external authentication.
512 – Indicates a login profile.
1536 – Indicates a default login profile.
2048 – Indicates an authentication mechanism specified in a login profile.