SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d68745dfcef613fdef9f565a515a52933059a805b4f2ae0602e5115be373cbf' 
  AND token = 'bQ+RnQ0e+tPLfhz6RQ8dCTOVvqU7pWdlfG992I+/PX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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