.NET Framework 4.5 installed but not found in regedit

That's because you're looking in the wrong place.

Taken from the article “How to Determine which .NET Framework versions are installed” at Microsoft Docs:

To find the installed .NET Framework versions manually (versions 4.5 and later):

1. On the Start menu, choose Run.
2. In the Open box, enter regedit.exe.
   You must have administrative credentials to run regedit.exe.

3. In the Registry Editor, open the following subkey:

   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full
   

   Note that the path to the Full subkey includes the subkey Net Framework rather than .NET Framework.

   Note

   If the Full subkey is not present, then you do not have the .NET Framework 4.5 or later installed.

   Check for a DWORD value named Release.  The existence of the Release DWORD indicates that the .NET Framework 4.5 or newer has been installed on that computer.

   The registry entry for the .NET Framework 4.5.

   The value of the Release DWORD indicates which version of the .NET Framework is installed.

Value of the Release DWORD:        Version

378389                          .NET Framework 4.5

378675                          .NET Framework 4.5.1 installed with Windows 8.1
                                 or Windows Server 2012 R2

378758                          .NET Framework 4.5.1 installed on Windows 8, Windows 7 SP1,
                                 or Windows Vista SP2

379893                          .NET Framework 4.5.2

On Windows 10 systems: 393295   .NET Framework 4.6 
On all other OS versions: 393297

On Windows 10                   .NET Framework 4.6.1 
   November Update systems: 394254
On all other OS versions: 394271

On Windows 10                   .NET Framework 4.6.2 
   Anniversary Update: 394802
On all other OS versions: 394806

On Windows 10                   .NET Framework 4.7 
    Creators Update: 460798
On all other OS versions: 460805

On Windows 10                   .NET Framework 4.7.1 
   Fall Creators Update: 461308
On all other OS versions: 461310