SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29cc5460fa68abcda15e8ad5b48870cd78cbe41f37f02bc383395f43ec5a4463' 
  AND token = 'SlbTnhIk8XafWaPNQs6lFxPybitc5ANYOOxHZV5ywqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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