SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0de5050a813124c83ed6ebd36145f49b93156a79b88a90338b440c0bf48c9a8a' 
  AND token = 'OU8vV6q89DvOsWtQYmUmpMAbDmLkYyx4ZIdU2BmXd9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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