SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84efd702dd536fc8b7becbd243e8933031e140604568aad9846e7113a5cb96df' 
  AND token = 'UIhIHrJhYnTRXyhiy6I037/JgJklcJrw1wblA1tmD1U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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