Linux Mastering Development

AWS metric filter for JSON event with time stamp

I have below formatted log events in cloudwatch log {"datetime": 2020, "NumberOfThreads": "Ok"} Aabove event can be filtered using {$.NumberOfThreads = "Ok"} metric filter but unable to pick same event with different time stamp format. Help me to fetch below log event in metric filters {"datetime": 2020.09.16T16.10.40, "NumberOfThreads": "Ok"}