User account status showin as 'OPEN' but expiry date showing less then sysdate

Please find below SQL output

SQL>  select username,expiry_date,account_status from dba_users where account_st

atus='OPEN' and expiry_date < sysdate;

USERNAME                       EXPIRY_DA ACCOUNT_STATUS

------------------------------ --------- --------------------------------

SYSTEM                         01-OCT-12 OPEN

SYS                            02-FEB-14 OPEN

SYS_2                          02-FEB-14 OPEN

MGMT_VIEW                      01-OCT-12 OPEN

SQL>

My query is even expiry_date is less then sysdate How account_status is showing 'OPEN' or Why it's not updated expiry date while changing password?