regup - SQL call time out and no result

Dear Experts:

The below SQL has very bad performance. It's never get the result.

Please advise how to improve the run time and complete the SQL statement?

SELECT zbukr "Paying company code

vblnr "Payment Document

bukrs "Company Code

belnr "Accounting Document Number

gjahr "Fiscal Year

FROM regup "Processed items from payment program

INTO CORRESPONDING FIELDS OF TABLE gt_regup

FOR ALL ENTRIES IN lt_bseg

WHERE lifnr = lt_bseg-lifnr AND

bukrs = lt_bseg-bukrs AND

belnr = lt_bseg-belnr AND

gjahr = lt_bseg-gjahr .

Thank you very much!

Helen