SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '679f5b03eb0682a8b0f1ec64499cb46d6d71bfbce77a3ec7a8332b117e472b30' 
  AND token = 'u2Y/sKtXl5Ndmp8z0xiOw4znGaXvbVKwNQejjXYg5pk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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