For queries being cached, you dont have to get the results from the cache again with get. All you have to do is run the same query.

put this

if(!Cache::has('contacts'.$search)){
        $contacts = Contact::with('account')
                ->where(function ($sql) use ($search)
                {
                    $sql->where('FirstName', 'LIKE', '%'.$search.'%');
                    $sql->orWhere('LastName', 'LIKE', '%'.$search.'%');
                    $sql->orWhere('Description', 'LIKE', '%'.$search.'%');
                })
                ->where('IsDeleted', '=', '0')
                ->orderBy('LastModifiedDate', 'DESC')
                ->remember($minutes, 'contacts'.$search)
                ->get();
    }else{
        $contacts = Cache::get('contacts'.$search);
    }

to

$contacts = Contact::with('account')
                ->where(function ($sql) use ($search)
                {
                    $sql->where('FirstName', 'LIKE', '%'.$search.'%');
                    $sql->orWhere('LastName', 'LIKE', '%'.$search.'%');
                    $sql->orWhere('Description', 'LIKE', '%'.$search.'%');
                })
                ->where('IsDeleted', '=', '0')
                ->orderBy('LastModifiedDate', 'DESC')
                ->remember($minutes, 'contacts'.$search)
                ->get();

There's a problem with that relation:

// wrong
public function account()
{
     return $this->hasOne('Account', 'id', 'AccountId'); // keys are swapped
}

// change it to:
public function account()
{
     return $this->hasOne('Account', 'AccountId', 'id');
}

Thank you, that solved the problem. It is my first time using cache it is is simpler than I expected.