Passing additional params to GET_ONE

I am using React admin with Amplify. I have written my own custom data provider for fetching data as I didn't find any data providers that was compatible with Appsync Graphql. So now I have a Graphql model as such

type Task @model @key(fields:["id","timestamp"]){
  id: ID!
  user: User @connection(name: "MyUserTask")
  status: Status
  timestamp: AWSDateTime!
}

Here the primary key is id and the sort key is timestamp. I am able to get all of the Task in either ascending or descending order based on the timestamp but however I am not able to get a single Task as GET_ONE in data provider only gets the id as a param but to get one Task I need to provide both the id and timestamp. So how can I pass the timestamp along with the id when Show button is pressed.

PS: I have both the id and timestamp when am at the list view.