SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ecd11acc9f6df41a14e00fe7ef09876d39abdb83aa015960dc2ec54590f9e409' 
  AND token = 'QFvUKnnx1Q2jzaZzKGxqfguP02paLAlgLgIUGOeOzCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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