SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c32ef0cc6a3b4edd28b840944e1dc135a15ec912e7f409b049153d8d5d94f7e8' 
  AND token = 'gn9n4KXifcjVvGr8b+jjZ6rp71fCzSIoAJyvvUS85+A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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