SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'db361d7c7fe95ce24bfaf1dea40627bfe1d9b8f71a3561c862d59f0cbb99f58f' 
  AND token = 'EMtQ4Ef1FvMQ8yF+RQcQKxVCRth/YXOGeNHPQhkIrwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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