SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79ba78b769770515d4978ba396e2fa165cd9f6fc39de1a7a72911cd8b3ef9260' 
  AND token = 'M6fx4JsdOxe/HyOcozzoVd8ilDDI6kZlWvKJlo1wEmg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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