SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '12b9e1ae3fe0b4656042e6ecf8e6693d8cabda716822d971e6db113e1b6ff856' 
  AND token = '/hJ228GLh+fmPNHp+v4pNw2JihWsjbAqXhHiH70qVgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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