When update statement, the execute time sometime taking 60 second sometimes taking 1-2 sec. Total row count around 18 million. CARDID is our PK. Almost each 2-3 sec our system send a request to that query. You can find the query on below;

    UPDATE C
    SET
        [CARDTYPE]           =  @NEWCARDTYPE,
        [ICPGROUPID]         =  @NEWICPGROUPID,
        [CARDNUMBER]         =  @NEWCARDNUMBER,
        [PINCODE]            =  @NEWPINCODE,
        [SCODE]              =  @NEWSCODE,
        [STATUS]             =  @NEWSTATUS,
        [CUSTOMERID]         =  @NEWCUSTOMERID,
        [PROFILEID]          =  @NEWPROFILEID,
        [BALANCE]            =  @NEWBALANCE,
        [BALANCETYPE]        =  @NEWBALANCETYPE,
        [DECIMALS]           =  @NEWDECIMALS,
        [CURRENCY]           =  @NEWCURRENCY,
        [STARTDATE]          =  @NEWSTARTDATE,
        [EXPIRATIONDATE]     =  @NEWEXPIRATIONDATE,
        [PINCOUNT]           =  @NEWPINCOUNT,
        [PINDATE]            =  @NEWPINDATE,
        [INITIALPIN]         =  @NEWINITIALPIN,
        [INITIALSCODE]       =  @NEWINITIALSCODE,
        [UPDATEDATE]         =  GETDATE(),
        [ACTIVATIONDATE]     =  @NEWACTIVATIONDATE,
        [REGISTERDATE]       =  @NEWREGISTERDATE,
        [UNREGISTERDATE]     =  @NEWUNREGISTERDATE,
        [ORDERID]            =  @NEWORDERID,
        [RELATEDCARD]        =  @NEWRELATEDCARD,
        [LOADCOUNT]          =  @NEWLOADCOUNT,
        [REDEEMCOUNT]        =  @NEWREDEEMCOUNT,
        [ISCHANGED]          =  1,
        [ISPROCESSED]        =  0
    FROM dbo.[CARD] C 
    WHERE
        CARDID = @CARDID

Also we have some indexes on the that table. What can we do? We are really stuck. We added one filter more but it did not work.