**Describe the bug**
Under certain conditions the equals comparison between String and Date yields the wrong result. Range Comparisons with greather-than-equals returns the correct result set.

**How to reproduce**
* Which ClickHouse server version to use: 21.2.5.5 (latest at the time of this issue)
* Which interface to use, if matters: HTTP (but should not matter)

```sql
CREATE TABLE default.myTable (
	myDay Date,
	myOrder Int32,
	someData String
) 
ENGINE = ReplacingMergeTree
PARTITION BY floor(toYYYYMMDD(myDay), -1)
ORDER BY (myOrder)
;

INSERT INTO default.myTable (myDay, myOrder) VALUES ('2021-01-01', 1);
INSERT INTO default.myTable (myDay, myOrder) VALUES ('2021-01-02', 2); // This row should be returned
INSERT INTO default.myTable (myDay, myOrder) VALUES ('2021-01-03', 3);

SELECT * FROM default.myTable mt
WHERE myDay = '2021-01-02';
```

**Expected behavior**
The last query in the example should yield the marked row. Instead it returns a empty result set.

There must be a connection to the used `PARTITION KEY`. The issue fails to reproduce as soon as I do any changes to the `PARTITION KEY` setting.

const_arg = { left_arg_type->createColumnConst(0, arg_left->value), left_arg_type, "" };
                arguments.push_back(const_arg);
                arguments.push_back({ nullptr, key_column_type, "" });
                kind = FunctionWithOptionalConstArg::Kind::LEFT_CONST;
            }
            else if (const auto * arg_right = args[1]->as<ASTLiteral>())
            {
                arguments.push_back({ nullptr, key_column_type, "" });
                auto right_arg_type = applyVisitor(FieldToDataType(), arg_right->value);
                const_arg = { right_arg_type->createColumnConst(0, arg_right->value), right_arg_type, "" };
                arguments.push_back(const_arg);
                kind = FunctionWithOptionalConstArg::Kind::RIGHT_CONST;
            }
        }
        else
            arguments.push_back({ nullptr, key_column_type, "" });
        auto func = func_builder->build(arguments);
        
        if (!func || (!single_point && !func->hasInformationAboutMonotonicity()))
            return false;
        key_column_type = func->getResultType();
        if (kind == FunctionWithOptionalConstArg::Kind::NO_CONST)
            out_functions_chain.push_back(func);
        else
            out_functions_chain.push_back(std::make_shared<FunctionWithOptionalConstArg>(func, const_arg, kind));
    }
    out_key_res_column_type = key_column_type;
    return true;
}
bool KeyCondition::isKeyPossiblyWrappedByMonotonicFunctionsImpl(