Hi Tobias,
What you could do is first find the JSON object (i.e., the table row) in your table model, and use its index in the model to set the selected index:
var matches = $.grep(array, function() { return(this.firstName === "John" && this.lastName === "Doe");
});
if (matches.length) { var index = yourTable.getModel().getData().indexOf(matches[0]); //first match yourTable.setSelectedIndex(index);
}