SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9781b7778d47d471b407f159bc73b124b07f952cbf5b4097368edfc5433647b5' 
  AND token = 'Gd9Djz7LpGkShmAn81dqskBWRbZcnQseGBCLv7P4hFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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