SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26c5d4cfc383025abb71f1741e0304327d7d0dc30820ecbe79acd4032416bddc' 
  AND token = 'sB0poBKxpkaLHRPjx9YnqiftjDXjpStvpxRYoBxrqeA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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