How to get value from the Store by id?

store in such fields

    fields: [
    {name: "id", type: 'int'},
    {name: "name", type: 'String'},...

I need to get the id - name value.

I try so:

    var rec = Ext.StoreMgr.lookup("MyStore").getById(id);
    alert(rec.data.name);

what am I doing wrong?

extjs store
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