SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fab1b3829a045e17d805262bda4f1ad0870e3af616172a1bad2f1fafb5ab03fb' 
  AND token = 'cu5C3OEitHBtPjfPsaxv+Z5NxIXUrK10qmDIExBNfTc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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