SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8db8f5e20abef41349798411f5c672960e211f7ed7ce1f4219adef3a3d90be8' 
  AND token = 'pcUUffOHrN29T1nGECH+qXky3ABrVTo3g8hbThT697k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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