my question why the query not use the index in oracle 9i.

Hi All

I have one query show table access full when do explain plan table. I already check have index for the table.
my question why the query not use the index in oracle 9i.

explain plan for 
  2  SELECT DOC_TYPE_CODE,DOC_NUMBER   
    FROM BL_RECEIPT_REFUND_DTL  
    WHERE BANK_IN_BATCH_DOC_TYPE = :b1  
    AND BANK_IN_BATCH_DOC_NO = :b2  
    AND BANK_IN_BATCH_DOC_DATE = :b3  
    AND BANK_IN_BATCH_DOC_NO IS NOT NULL   
    AND BANK_IN_DOC_NO IS NULL  
    AND RECPT_REFUND_IND = 'R'  
    AND NVL(CONSOLIDATED_RECEIPT_YN,'N') = 'N' 
    FOR 
    UPDATE OF BANK_IN_DOC_NO NOWAIT  3    4    5    6    7    8    9   10   11   12  ;

Explained.

SQL> @$ORACLE_HOME/rdbms/admin/utlxpls.sql

PLAN_TABLE_OUTPUT
--------------------------------------------------------------------------------

-------------------------------------------------------------------------------
| Id  | Operation            |  Name                  | Rows  | Bytes | Cost  |
-------------------------------------------------------------------------------
|   0 | SELECT STATEMENT     |                        |     1 |    48 |  2698 |
|   1 |  FOR UPDATE          |                        |       |       |       |
|   2 |   TABLE ACCESS FULL  | BL_RECEIPT_REFUND_DTL  |     1 |    48 |  2698 |
-------------------------------------------------------------------------------

Thank you

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Edited by Lalit : Added code tags to preserve formatting