Replacing select query having where condition of range ,from DB look up

Hi Experts,

I want to replace below query in ABAP from BRFplus

s_matnr is select option of matnr type containing below data:

000001

000002

000003

ts_mara contains only one fields:

SELECT matnr

FROM mara

INTO TABLE   ts_mara

WHERE matnr IN s_matnr.

Now in BRFPlus i am not getting any option for 'IN' operato, hence i have created a look expression inside that i am using DB look up.

But thats giving performance issue.

Kindly suggest.

Regards,

Khushbu