Problems with json when searching data with php and ajax

Dear I have an ajax that brings me data from the database with php to a table the code is the following

Ajax:

$('#selplan').change(function(){
    var idplan = $('#selplan').val();

    var consulta = $.ajax({
        type: 'Post',
        url: '../Model/buscarplan.php',
        data: {plan: idplan},
        dataType: 'JSON'
    });


    consulta.done(function (data) {
        if ( data &&  data.error !== undefined) {
            $('#estado').html('Ha ocurrido un error: ' + data.error);
            return false;
        } else {
            if (data.Minutos !== undefined) {
                $('#datosplan #txtMinutos').val(data.Minutos);
            }
            if (data.Datos !== undefined) {
                $('#datosplan #txtDatos').val(data.Datos);
            }

            return true;
        }
    });
    consulta.fail(function () {
        $('#estado').html('Ha habido un error contactando el servidor.');
        return false;
    });

})

my php:

<?php namespace Model;

$conexion = new \mysqli("localhost", "", md5(''), "");

if ($conexion->connect_error) {
    echo "Fallo al conectar:".$conexion->connect_error() or die();
}

if (! empty($_POST['plan'])) {

    $idplan = $_POST['plan'];
    $query = "SELECT IdPlan,Nombre,Minutos,Datos FROM plan WHERE IdPlan = $idplan";
    $result = $conexion->query($query);
    die(json_encode($result->fetch_array()));
}

$conexion->close();

before I had two records in that table and I looked well and I load the data but I added a third record and that special does not bring me the data returns null, any suggestions? here I hit the error

  

Validate.js: 96 Uncaught TypeError: Can not read property 'Minutes' of   null       at Object. (Validate.js: 96)       at i (jquery.min.js: 2)       at Object.fireWith [as resolveWith] (jquery.min.js: 2)       at A (jquery.min.js: 4)       at XMLHttpRequest. (jquery.min.js: 4)