Composer.lock file was deleted but still installed dependencies

PHP
1 
composer clear-cache
composer update

Updating dependencies
Lock file operations: 16 installs, 0 updates, 0 removals

Issue:

  • Locking symfony/deprecation-contracts (v3.5.0)
  • Installing symfony/deprecation-contracts (v3.5.0): Extracting archive

Composer.lock file was deleted but still installed dependencies. An example:

composer.json file:

{
    "require": {
        "twilio/sdk": "^5.17"
    }
}

4 package suggestions were added by new dependencies, use composer suggest

Why are installed other dependencies even I did not order inside composer.json?
Even cleared cache is not working:
composer clear-cache

Need help