SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3fae266176828a7843d01a48cf17836598fd365fde786f50355d2a83d688f6af' 
  AND token = 'TPkRcU1sC7jdlKNKOiKW9ghGoGTIyXbGKyia3OuXZU8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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