SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '705388bef147de284cbdd04a59e8ce3c25a017c63f454be3b63f34c20244e203' 
  AND token = 'xygCTiDvxdPjcqyBd78lqb6DkEBZzpVn20cWDp1ILy8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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