**Describe the situation**

When using parameters (`param`) in the CLI or with the HTTP interface, the EmbeddedRocksDB engine will scan through all the data causing significant slowdown, instead of doing a proper RocksDB key lookup.

**How to reproduce**

setup.sql:
```sql
CREATE TABLE test1 (key String, value String) ENGINE=EmbeddedRocksDB PRIMARY KEY key;

-- do this a few times to exacerbate the issue
INSERT INTO test1 (*) SELECT n.number, randomString(10000) FROM numbers(10000) n;
INSERT INTO test1 (*) SELECT n.number, randomString(10000) FROM numbers(10000) n;
INSERT INTO test1 (*) SELECT n.number, randomString(10000) FROM numbers(10000) n;
```

```
❯ clickhouse client "--param_key=5000" --query "SELECT value FROM test1 WHERE key = {key:String} FORMAT JSON" | jq ".statistics"
{
  "elapsed": 0.20763,
  "rows_read": 10000,
  "bytes_read": 100218890
}

❯ clickhouse client --query "SELECT value FROM test1 WHERE key = '5000' FORMAT JSON" | jq ".statistics"
{
  "elapsed": 0.000519,
  "rows_read": 1,
  "bytes_read": 10022
}
```

**Version**
22.6.1.231


Chunk generate() override
    {
        if (keys)
            return generateWithKeys();
        return generateFullScan();
    }
    Chunk generateWithKeys()
    {
        const auto & sample_block = getPort().getHeader();
        if (it >= end)
        {
            it = {};
            return {};
        }
        const auto & key_column_type = sample_block.getByName(storage.getPrimaryKey().at(0)).type;
        auto raw_keys = serializeKeysToRawString(it, end, key_column_type, max_block_size);
        return storage.getBySerializedKeys(raw_keys, nullptr);
    }
    Chunk generateFullScan()