SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34224e1960d369f468347e14b92b0bd55ad1964d419b9cbba16766b56f75a3f2' 
  AND token = 'Uuy2CGYp7AVBQ9qEHs7sJl4qYuKgtTVvGOEkKHFCaUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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