SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c85fac2b24ce4bbf5cfda52677aedb7a06aec6697ad31ff93052ccc18af79794' 
  AND token = 'P0Q+YEA9NrPl6/yvPhqpdoEe2bDuVz+GkAm8/IY+FgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}