SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '430ccc641b780a7f4c55358a43adae3f1d23d73302890810c3daaa5d4e709c52' 
  AND token = 'M3QOtHvjRYI+Z/VHoBi8mNTYG+VzWfvnK9RGbtHgVt0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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