SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '103cc9a7c5da97811406c6ff891ca94032eda3498564a8be24ba6040596ae094' 
  AND token = 'N7aNbpTXkWVyuCpiiYB58CNBZTbbd1LU6Z3xmYwoYJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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