SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '841b122f4e1ce50d61ad77caaa33d0a4291a0568265a658e1d5c051330fa85a5' 
  AND token = 'XtSzEjewq6Gq4TWvNXONNYZxnkB8RAYr7YZJHF7mvx4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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