SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40c16891aa10a0f6ec571d8846c03a3c4bdf1f85dcede717367d42d7d683fb7e' 
  AND token = 'GJNkQsx4RP1VhwhsBeLCse+WQAR6Hr7ct1C8uasIzKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}