Unable to delete record via API using the EX operator

Hello,

I am unable to delete a single record use the 'EX' operator. I can successfully delete all records using the 'GT' operator but I would like to selectively delete records. Below are the payloads I am sending to the API. Please advise.

EX example:

{
"from": "<table_id>",
"where": "{'3'.EX.'109391'}"
}

EX response: 405

    {
       "message": "METHOD_NOT_ALLOWED",
       "description": "Error APIKIT:METHOD_NOT_ALLOWED"
    }

GT example:

{
"from":"<table_id>",
"where":"{3.GT.0}"
}

GT response: 200

NOTE: Http verb is the same (DELETE) for both requests, so the error message is not correct.