The biggest problem with the current query is that it's not possible for an INDEX SEEK (and subsequent range scan) to occur on the r_mod_time column because of the formulas you have wrapped around the column. This is how to fix that as well as impart what most people would be some "best practices". Of course, you have to have the correct indexes, as well.

SELECT x.bay_user_id

, x.fr_acid

, c.c_m_phone_no

, c.c_email_id

, x.txn_amt,

, x.end_date

FROM dbo.cusr c

JOIN dbo.xfrq x ON x.bay_user_id = c.bay_user_id

WHERE x.r_mod_id = 'FTONLDISP'

AND x.res_code = 0

AND x.r_mod_time >= '20130413' AND x.r_mod_time < '20130414'

;