SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f28fa15d166f72bff634110cf96192ace83aac0c59125f4365bb24226f55432' 
  AND token = 'OjWx+k6p7TQHzKWuGhQFoKHHBrNgWpkSPuBHCCmp468=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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