SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2bb03ce457b47638a91153793aea64c9cc8b7d5ad50dd0c3b4a5d69223fc68c2' 
  AND token = 'z8lHZRRbyPdoZM8GNMwUNqLy+D+T8QiDHQWyNLelmZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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