Without query parameters, all executions of a particular workflow will be returned. You can query them based on the input fields in the response. For instance, if an input object is returned as

// (...)
{
  "input": {
    "paymentMethod": {
      "name": "card",
      "info": {
        "type": "credit",
        "issuer": "DATATRANS",
        "brand": "MCI CREDIT",
        "usage": "consumer",
        "country": "CH"
      }
    },
    "reference": "dt-1127",
    "amount": 50.5,
    "currency": "CHF" 
   }
}
// (...)

you can then query it by any of the elements listed in input. For example, the queries /api/v1/workflows/{workflowId}/executions?reference="dt-1127" or /api/v1/workflows/{workflowId}/executions?paymentMethod.info.type="credit" will filter all executions matching these fields.