SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03d69a7b974369c61f8b3d2902e77e9ff20af47587c29d41f557729e3c3c5e36' 
  AND token = '/iKxZEp0JAz9wC/OYO8FSP/HUX5ii5kDfCtwqCRMIqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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