slow execution of Query

Can any one help? to make it faster.

SELECT  vbfa~rfwrt AS rfwrt

      vbfa~vbtyp_n AS vbtyp_n

      vbak~auart AS  auart

   INTO  CORRESPONDING FIELDSOFTABLE  tbl_t1  "  DEBITNOTE

   FROM

   vbfa

   INNER JOIN

   vbak

   ON

   vbak~vbeln  EQ vbfa~vbelv

   WHERE  vbak~vgbel IN s_vbeln

AND vbak~kokrs EQ'BM01'AND vbak~bukrs_vf EQ vbukrs

   AND    vbak~audat IN s_audat

   AND (

     ( vbfa~vbtyp_n EQ'P'   "P FOR DEBIT NOTE

     AND vbak~auart EQ'ZDR' )

     OR

      ( vbfa~vbtyp_n EQ'O'

     AND vbak~auart EQ'ZCR' )

     ).

Regard

khurram Nagi