SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abec66194366af651d2ea146024bae084d0c4fe2b1ead6d9c41a5ab522d11bb0' 
  AND token = 'k0pfkRsK6kMSxAzyDzAEGGUrfWAAuWJSiF9PIQStAxk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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