Performance Issues while executing LT27 transaction

We are getting a 'Time Out' error while executing the transaction LT27. The reason for this is an expensive select statement on LTAP in the standard code given below.

select * from LTAP appending table iltap

where nlenr eq lagerein

and lgnum eq lagernum

and pquit eq con_x

and kzsub in kzsub_tab

and (DS_clauses-where_tab)

%_HINTS

DB2 '&SUBSTITUTE LITERALS&'

DB6 '&SUBSTITUTE LITERALS&'

ORACLE '&SUBSTITUTE LITERALS&'

MSSQLNT '&SUBSTITUTE LITERALS&'.

One possibe solution for this is to create a secondary index on NLENR field but we want to avoid that because we already have 5 secondary Indices on LTAP. We already implemented the SAP note 999743 but it was of no use. Please reply ASAP.