SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58d91a89f87da72e358dd9e1655c0f87d5f5f03e3a67561d2817f4205ae2f295' 
  AND token = 'OxdOqKkz4bywXeYGher8tqwiKJ9xqpxvzH9CzTVIDM0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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