SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0afbd661f603784327426663fef5b45d13dc3206c892c96fbfea7f1b441c025' 
  AND token = 'HUFAxvozoqSwY3kLa2dsn7uYNg/RCKZxhXLhzt69Epk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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