SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8b68efadda32cc8954496d4ab42cb81b9272cc9fa3a32b9c085b17e72c1ff4e4' 
  AND token = 'eA/UPNnbhCJMfOLoIWaISVH4AjqP8/CT+Rihwd8y4RM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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