SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca6ceb749721662eb149b4db9f508f72a97e39d979e563e46944c44d98173f22' 
  AND token = 'rNqGslC61NCILwvW+W1U8RxJhVLkjI12eioInFZNzho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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