SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c0c172c08948fae87338b94bc1fd721a049a5922786794f564985c78dc45d03' 
  AND token = 'YTf9ZZLNpLdrugU+0BD2KpFV/v8VhDNVisTnMiNSepg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}