SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8f3f98499df00e4c542a62c8c39eccf8ae167b29eb46f61124f081d196e612b2' 
  AND token = 'vp9KJ5YhtYeNoGjso63lkXZYWWE7USF4txun6kqgEHM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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