SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39a9bb761fd9726210c7d07ca6216049287be9d7b164a4ff348b391e423afeb7' 
  AND token = '1RbYNJnB6Y3A8/P8gUXdM9MzwvwHGJZZiOqrKEwTqiY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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