SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '398261b3675410809e3d3eb01816ef4b5c3b2b7a6d6ecac064ff9979bbebdead' 
  AND token = 'FSNkfkBnC8pQoUUqdf4dWXen5uVWHv7XZv/UQLwGbmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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