question about where clause of CQL update statement

[John Sanda]

I am using CQL 3 and trying to execute the following,

UPDATE CHANGELOGLOCK SET LOCKED = 'true', LOCKEDBY = '10.11.8.242
(10.11.8.242)', LOCKGRANTED = '2012-10-05 16:58:01' WHERE ID = 1 AND LOCKED
= 'false';


It gives me the error, Bad Request: PRIMARY KEY part locked found in SET
part. The primary key consists only of the ID column, but I do have a
secondary index on the locked column. Is it not possible to include a
column in both the set clause and in the where clause? And if it is not
possible, how come?

Thanks

- John