SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52cbf445637a852bd5fb36b13602bd6ae514847a4e917f14b6fee89fcc1e13bd' 
  AND token = '4bztM0ld7l5meyxpjE8um+WKtCXqLHWgMKgGjq8svoY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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