SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12546d37891ce678bbf841659829f7d80b9995e4eccdb57af958dc9fcee11a32' 
  AND token = 'yt3lPt5+URsIJY9xdwwxEHZXDgRFbGn4nuf0lJmoaiA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}