SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fad5b27ff61710573423630aade60d23da2b36c0f5c000147afc5312fe0a7f1d' 
  AND token = 'uag0MajWK2NnF9Iho9f/fHkQk3ZK1vWG088fH9hhmno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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