11GR2 : sql consuming lot of CPU

Hi ,

We have the following sql being run as part of bigger program.  It is executing 1100+ times an hour .   The sql itself executes in less than a second.  However the cost is very high.  

SQL

SELECT HP.PARTY_ID FROM HZ_PARTIES HP WHERE HP.PARTY_TYPE = 'PERSON' and

  2  LOWER (HP.EMAIL_ADDRESS) = lower('emailaddress');

Execution Plan

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

| Id  | Operation         | Name       | Rows  | Bytes | Cost (%CPU)|

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

|   0 | SELECT STATEMENT  |            | 17982 |   561K| 23134   (3)|

|   1 |  TABLE ACCESS FULL| HZ_PARTIES | 17982 |   561K| 23134   (3)|

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

Statistics

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          1  recursive calls

          0  db block gets

      83455  consistent gets

      83319  physical reads

          0  redo size

        336  bytes sent via SQL*Net to client

        509  bytes received via SQL*Net from client