SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a9b54012f8f3ef751e7fdda376c4bbf9be9d4ff6b51725b6b3476c9aaa8cd0a' 
  AND token = 'SjuajGkkVwSozizPD81lPJukLOLq+h9JmYV0cXuPVoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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