As zasiditsya from sql injection without OOP in php?

PDO and prepared statements, read more https://habr.com/post/148701/

And where does the fear of the PLO?
In documentation is described how to attach the parameters to the query as in object-oriented style and procedural. To implement the communication with a DBMS can be in fact, and in another style, if we are talking about MySQl.
\rphp.net/manual/ru/mysqli-stmt.bind-param.php

PS: You're just afraid to learn the documentation trying out various examples of implementation. That's all.

Read carefully and understand how to operate the PDO and Google about prepared queries.

I hasten to please. Knowledge of OOP is not required for this. You can just do as many examples to work with PDO as an instrument, without going into details.

But better still take the time to learn at least the OOP syntax in PHP. It's nothing challenging, but great to make life easier.