Getting a takeaway is, statistically, safer than buying packaged food in a supermarket.
Your takeaway will have been handled by only one or two people (the delivery driver only handles the plastic bag). A tin of baked beans could have been handled by dozens of people in the long journey from factory, to lorry, to warehouse, to lorry again, to supermarket shelf. Unwrapped fresh produce in a supermarket could have been handled or coughed on by hundreds of people!
The official statement from the Food Safety Authority is that thorough cooking kills coronavirus. So even on the vanishingly tiny chance that the cook was infected, was somehow permitted to remain in a kitchen despite being visibly symptomatic, and was stupid/homicidal enough to actively cough directly into the cooking pot, you could still eat the food and not get infected.
Corona sticks to different surfaces to different degrees. For example it doesn't last or stick especially well on cardboard. It lasts three times longer on metal. So a pizza box is statistically far safer than tins.
You can't hermetically seal yourself away from the world. Every time the postie visits, that's exposing you to items that have been handled by far more people than your takeaway. But no one is doing a Vernon Dursley and nailing their post slot shut.
Besides healthy non-elderly people seem to be forgetting that all these safety measures - social distancing and self-isolation - are not to protect YOU, but to protect vulnerable people FROM YOU. All these measures exist to reduce the number of critical cases and thus flatten the curve and reduce pressure on the NHS. So many posts from people freaking out acting like they're about to keel over just because they went outside or touched something. If you are not elderly or at-risk then even if you did catch it you'd probably not have any symptoms or at worst have only mild symptoms. (Cue posters lining up to share anecdotes about how their 32-yr-old rugby playing DH went into the garden and waved at Doris from next door and fell over dead five minutes later.)