SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c693974668a718bf6fe2d3e88484bca5e03574f49fbcbd30fa7f6dde1cd936f' 
  AND token = 'g5wUzLT46uqYckYexlhEi+lkyOqvtqCGVGtmLz5A1uY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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