Hello Sumeet,
1. can you please check if there exists any secondary index for the tables "but021_fs" and "adrc" with the fields in "where" clause.
If these is no secondary index, please create a proper secondary index.
2. change the Read statements as below.
SORT lt_partner by addrnumber.
READ TABLE lt_partner_crm INTO ls_partner_crm WITH KEY addrnumber = ls_adrc-addrnumber binary search.
SORT ct_partner_keys by partner.
READ TABLE ct_partner_keys INTO ls_partner_key WITH KEY partner = ls_partner_crm-partner binary search.
This will increase the performance.
Br,
Navn