SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b40dc235331d6891b09182c295ebe073ac4dabb8282283bc87561b0dee3b7167' 
  AND token = 'IMlQZt+NwPRKgbr23iuWlUVm5OH2aaNAruFELIfnvjI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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