SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '249f7743515291751cce2eed47be8a35a209388eedda99bd7e5b559aee261bbd' 
  AND token = 'wsIGeq8uMCExl2KfzTnZPhuJ4BN49kYDowYCpPICk5I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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