SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a68cf9ec921beb1cb4e29ad8a204d1b603d228ce2f30d280a622a65a4dffd6c8' 
  AND token = 'KiR+B9bYrfwcNlOFVzsehEIvrida1WJRZORZjUP/W6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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