Splunk connector with rest api call action

Hi, I recently started working In FortiSOAR.
In playbook I am using the splunk connector with FSR: rest API call action and GET HTTP method to collect the kvstore lookup data.
The kvstore lookup contains fields including Date field (which contains ephoc format of date).
The Playbook is picking all the data without any issue.
But I have to pick data based on condition (if date is beyond 1 month I have to pick those data)
Could anyone help me how to achieve this.

Thanks.