SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ea7252a99398ec9b0d80ece7c2d3bbb56f973fea697684c6673401f7871e831' 
  AND token = 'b3kYwQAX2MlXR9EaYoYlKRmlKVDnzSWPXTlkau4rT8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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