SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38971e3c3eeaeb860e3d6426a4446b5f090c879e0940e56e9cda83c32c8ecdc1' 
  AND token = 'ngv1I+3xcxkLvyRoAXCkJ4/5Bs+C5eU+rmgNQbEabU8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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