SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56577382e35669f3861d7dfc82b360a0327a2240f61e9326828928f60344cbb6' 
  AND token = 'L731wZ0hacNwE8zQoKDvjEae4hfYh29Lcfjyk8p0Zdw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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