Unique validation rule not applicable to db index

Schema::create('users', function (Blueprint $table) {
  $table->id();
  $table->string('first_name');
  $table->string('last_name');
  $table->string('email')->unique();
  $table->timestamp('email_verified_at')->nullable();
  $table->string('password');
  $table->rememberToken();
  $table->timestamps();
        });

TextInput::make('email')
  ->required()
  ->unique(table: User::class, column: 'email')

SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '[email protected]' for key 'users.users_email_unique'