SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9683df52661f37b4ea920b58467601c7faa99efc29e787a420ca8fbb86c31678' 
  AND token = 'nKtSYYIhoXenk+nvIFKmC3BEud3H90W6fuvc2YKRb7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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