SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ab99876f4fa599ae29ebc095d80afd6d68f6aa430cc8ef2b40c239c0db6e8a8' 
  AND token = 'dN9wFI7lhK3jh+qiZUr0HzHOjgNZQRddDOBGx9F7CVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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