SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '740136a3a9f9184c2cb42e6cfac2bcee4394b73cc8b1afa3fd9c5947e043c542' 
  AND token = 'm/dn4ABrz04W548Bnnwk8WC4P+Z7pdZISLXb5fnyK7w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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