Control-Command-Space opens Search When I use the  Cmd ⌘   Ctrl ⌃ 
 Space  , It does not open the Emoji viewer, but opens a 'Search My Mac' in the Finder.
You need to make sure that key combo hasn't been set up as a new command in System Prefs > Keyboard > Shortcuts > Spotlight

Default should be  Cmd ⌘   Opt ⌥   Space  



You could also check it wasn't added as a specific menu command in App Shortcuts...


...which would then show in the Finder's File menu too [together with a new 'Find By Name' item] compared to the original using  Cmd ⌘   F