SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '447e5f7ff7108bffbc96b89b5e2bd53aec894f907a46da086e018d54edbd2e2d' 
  AND token = 'goEzXqWiXsCs5viAOuZHhkFVQZQP+mIuzYw1CXxoUAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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