SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '019a090f976e14f3b608e0de2d0aba7b178c3a89968465d53db80672e55afe3d' 
  AND token = 'NdlSymrM8asGCDCe/ZRCmoVTbNiEgtWIu/h9MiWrgBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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