SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b603e7187c61e60019108ec29e8c34417a04ba86cfab45c3a6f5011fe41a240' 
  AND token = 'CdrXPQFeYUWx1voJ5wCELTPQOyyhgQg8SlkwzQuZClI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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