SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7cc824688cfd9164d55f8b8105bc0f4f594a43cbfda8f0d28b4f901881a26ec' 
  AND token = 'Ac24dk/2KGZWLwxvFSTcLVZpqhwZDg1l5v7Z/JAaaWg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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