SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '2645b9c4df05ac815c3aa278460916df09b267c9bca6e5e77b0f4af90a9a0ad4' 
  AND token = '/tzoqlU7Lg0BANBEQv7lBPdKA+Bj7eW4hcz5whfRtkA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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