SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42b45f6b195da1ff4270bc7f8d6297ade858ec8c8fb6ccb2d2f3daee9e5af4e2' 
  AND token = 'kU4wLZH5+KWzgtmBYO+433yQY/qY4RTiYoJ6528me9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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