Performance issue with api/collect endpoint

Cross-posting from [here](https://github.com/oss-review-toolkit/ort/issues/10258#issuecomment-2862846296) for visibility, querying https://public.purldb.io/api/collect/?purl=pkg:npm/asdf@1.0.2 takes close to 30s (for getting a 4k JSON response):

```
$ time curl https://public.purldb.io/api/collect/?purl=pkg:npm/asdf@1.0.2
...
real 0m27.074s
user 0m0.020s
sys 0m0.018s
```

which seems to be extremely slow. For our use-case to speed up ORT scans by retrieving existing scan results for packages, this is problematic.

Is this kind of performance expected? Is there any way to speed things up?