SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb7c60e106c7f5f036c6f2a295c67d34ad08b1da28d01d95060d754bb77995a3' 
  AND token = '8DXaA7JPVPdnWYvDglG0K1QkLq5+5Jjyz40XjaBgNC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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