SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa5141f0f1cf6afd98c401ae441623afe6e99b381819beef9a514baee3a27bd3' 
  AND token = '66BUjx+HXEIZovaIT8BrrURhF64LYdyquNpTYOdCYmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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