SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6498204290266190158145daff2599dcad1fd217deb304b90349806f0d86a72' 
  AND token = 'BYO0kFMFDYQ9+bJ5USQZ8Q8jaTFdti9qiACBp8RrKBQ=' 
  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"
    }
  }
}