SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0475b933caffa9d8841e2fe765a2d11edbabb0f131296bd73f963699872170ab' 
  AND token = 'rgtneUIPpGAOQNdFQCDlOeW4HAJ7lKjds66sllqLm0g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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