This step is unnecessary if the `product_name` and `version_string` doesn't match. 
Can you change it to:
```python
    for current in context['currentversions']:
        if (
            release['product_name'] == current['product'] 
            and release['version_string'] == current['version']
         ):
            current_end_date = (
                 datetime.datetime.strptime(current['end_date'],
                           '%Y-%m-%d')
            )
            if end_date <= current_end_date:
                active.append(current)
```

I know we're talking about "optimizing" microseconds but there's also value in keeping the code pure and more "correct".