Hello, @kumar kaushal ,
It is quite normal for the Antimalware Service Executable to utilize high CPU usage. But as a background task, the Service is not supposed to utilize fore than 50% of the CPU resources. Since msmpeng.exe is the default program in Windows Defender or MSE, you cannot remove it. What you can do to resolve msmpeng high disk usage or high memory is to make adjustments to Windows defender or MSE.
Not quite sure of how you managed the Windows Defender exclusion from Scanning MsMpEng Files, but this is one of the occasions when Windows Defender process MsMpEng.exe will not eat up 100% CPU on Windows 10 anymore.
Other solution would be to reschedule Windows Defender Scan by changing the settings in the New Trigger window,for example the start time for scanning. Try to open the task manager and then check whether or not Windows Defender process msmpeng.exe still occupies much CPU
Disable Windows Defender in Group Policy:
Local Group Policy > Computer Configuration > Administrative Templates > Windows Components > Windows Defender Antivirus.
Under Windows Defender Antivirus locate and double click Turn off Windows Defender Antivirus to configure it. Then In Turn off Windows Defender Antivirus, set it as Enabled and then hit Apply and OK to disable Windows Defender
Of course you can always go for disabling the Microsoft Security Essentials
I hope this opinion will help you further,
Regards