SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd946052a1f676a1579ae1ca46f47674bfcb472c4228ed1193acc3fa9ffdc3c9c' 
  AND token = '2ayJDWNcTWBr91aQFJE8jvnbEjxSVzWHD9I/EP2i9uU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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