SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37ee6a909bb06d494eb095ef3a19b4bbea3a042a1848b56ca034211fcc065f0f' 
  AND token = 'ZUFSRd7mEl8xzfHJqNjRgyiEgfJhkp9K9SjtM59mDvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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