MSEG select performance problem - Please help me (URGERNT)

I have the following SELECT stmt which is taking more time to execute......Kindly help me how to improve performance ...

YOUR HELP IS HIGHLY APPRECIATED....

SELECT a~mblnr

a~matnr

a~werks

a~charg

a~lifnr

a~bualt

a~erfmg

a~ebeln

a~ebelp

b~budat

INTO CORRESPONDING FIELDS OF TABLE it_mseg_mkpf

FROM mseg AS a INNER JOIN mkpf AS b

ON a_{mblnr EQ b}mblnr

WHERE a~matnr IN s_matnr

AND a~werks IN s_werks

AND a~lifnr IN s_lifnr

AND a~bwart EQ p_bwart

AND ( a_{ebeln NE ' ' AND a}ebeln IN s_ebeln )

AND b~budat IN s_budat.

IF NOT it_mseg_mkpf IS INITIAL.

SELECT matnr bismt zzshelf_life FROM mara INTO TABLE it_mara

* FOR ALL ENTRIES IN it_mseg_mkpf*

* WHERE matnr = it_mseg_mkpf-matnr.*

ENDIF.

IF NOT it_mara IS INITIAL.

SELECT matnr maktx FROM makt INTO TABLE it_makt

* FOR ALL ENTRIES IN it_mara*

* WHERE matnr = it_mara-matnr.* ENDIF.

Thanks in advance,

Regards,