Parallel Execution of Query

Hello All

Can anyone help me on this below query

SELECT    
DEFICIENCY_COLLECT_DIS 
      from  DOC_REQUEST doc
 WHERE        EXISTS 
                            (SELECT    null
                            from        template t,
                                        LETTER_TYPE LT
                            WHERE     T.CMS_DOC_TYPE_ID = LT.CMS_DOC_TYPE_ID
                            AND       T.CMS_DOC_TYPE_ID = DOC.CMS_DOC_TYPE_ID
                            and       t.template_nm     =  doc.TEMPLATE_ID
                            )
 AND CMS_PRINT_STATUS IN (1,6)
 AND CMS_DOC_TYPE_ID IN (1,5,10,11)
 AND CMS_USER_REQ_ID = '999999999'
 /

Took 26 sec to execute the query

Count of Doc_request  --> 1142206

Count of template --> 10

count of Letter_type --> 42

Column CMS_PRINT_STATUS  ranges from 1-6, cms_doc_type_id ranges from 1-11 only .