SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cda5dbdd0c663ac69fb576ce92034e6527341238bdd4864bb376703f6e3beb9' 
  AND token = 'bYuG40Kj6nURHxA9bREc1ZJvbukg8msfdFh3imOICw0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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