SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa52492f20f1bf5e034e72eb40e4a636fc943a355436bd57e9207319eb946480' 
  AND token = 'BKQcvjkX8uwFuP54fFbHvkuvnfSDvkD7jrE9DlIS15E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}