SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '6f9a2ee9f92f82b2ee9fa01fa72771647471ec21455412a17b8ecd1abd1d9a55' 
  AND token = '0WQLnjByYcTV6BQWsUr7ju+NgMOP9Ddt6I6aPFzoiF0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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