How to make friends composer and php-cgi?

Question

PHP

Hello!
The essence of the problem is this:
I need PHP7. On hosting, it works only in CGI mode. PHP5.4 is built in as a native Apache module. I have it configured in my control panel that the PHP handler is php7.1 via CGI. Scripts from PHP7 work correctly, checked.
I want to use composer to install a package (specifically edamov/pushok, if that matters).
Composer says I have PHP5.4 and the package doesn't meet the requirements.
I run composer with the --ignore-platform-reqs flag.
Composer says again that I have PHP5.4 and the package doesn't qualify.
What should I do?