SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e39bf6fc974592750e8fee22e110c5cfa1948178ea2ca891f8cf5337b9814309' 
  AND token = '9O2ujWA1nzwMMteVOdnev6kZvRPcI/4uXvJoUic9gP0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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