Routine query

Hello, I have a query about a routine.  I want to do a look up in a DSO but the DSO is very big. so when i do select i only want to select one row of my selected data. what would be the syntax of the code?

SELECT CUSTOMER ZBSTTIME ZBSTDTE INTO TABLE IT_MBB FROM /BI0/AZBW_MBB00
FOR ALL ENTRIES IN SOURCE PACKAGE
WHERE
CUSTOMER = SOURCE_PACKAGE-CUSTOMER AND
ORDER   = SOURCE_PACKAGE-ORDER.

Thanks.