SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3679f24ffb2a8962e547053d541efc10f35bc6246bd428364eae849618383a33' 
  AND token = 'JnUTUZ6jviNWp+mgt7MyDBziUYbEQA2SYhoqNY28v6A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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