Speed Issue, Query Takes 7-8 Min

I'm running this query off a table of about 1.5mil records. If I leave the date parameter off It comes up under a minute. When I add it back, it takes 5 minutes before the query even starts running. All the fields used in filtering the query are indexed. Any ideas to speed this up?

SELECT CallsEntered.[Work Order Nbr], CallsEntered.[Date Entered], CallsEntered.[Time Entered], CallsEntered.[Primary Locator Code] AS [ASC], CallsEntered.Headend, CallsEntered.Node, CallsEntered.[Grid Id], CallsEntered.[Q Code], CallsEntered.[Problem Code 01], CallsEntered.[Primary Finding Code], CallsEntered.[Primary Solution Code], CallsEntered.[Cancel Code], CallsEntered.[Scheduled Date], CallsEntered.[Wo Status], CallsEntered.[Date CheckIn], CallsEntered.[Assigned Installer], Calendar.Week, Calendar.Year
FROM Calendar INNER JOIN CallsEntered ON Calendar.Date=CallsEntered.[Date Entered]
WHERE (((CallsEntered.[Date Entered]>=Forms!frmServiceCalls!txtStartDate Or Forms!frmServiceCalls!txtStartDate Is Null)=True) And ((CallsEntered.[Date Entered]<=Forms!frmServiceCalls!txtEndDate Or Forms!frmServiceCalls!txtEndDate Is Null)=True) And ((CallsEntered.Node=Forms!frmServiceCalls!txtnode Or Forms!frmServiceCalls!txtnode Is Null)=True) And ((CallsEntered.[Primary Locator Code]=Forms!frmServiceCalls!cboASC Or Forms!frmServiceCalls!cboASC Is Null)=True) And ((CallsEntered.[Q Code]=Forms!frmServiceCalls!cboQCode Or Forms!frmServiceCalls!cboQCode Is Null)=True));

Thanks