SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6945209075f2cc31533fe13062cda13005883419ffe8c51a3daf20622d16341' 
  AND token = 'fV4yWaJp+mBjYhBEGxD9rmeBXCe4UEwbJfDzE0TtMu4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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