SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3838925a8d51f172d98f4ce36e946a5ab270525bdcc7beb67cf698c03e33e5c2' 
  AND token = 'OEsjYFBgd2hNMc62JVDh5/u6oGZRgqVunS6xxbfu+M0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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