SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '40d0a4b6f53183b74b1231fc674367b0dd448763f2f8efa603514a4f3d09e906' 
  AND token = '39f0MifRi/5h/AIymEDHOE+ISmjt6AVwUzZmx0LfqM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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