SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fb5535c22db8506b654fde7c7e0b2a5937295a574b12b2bc7bcc4db6612f314' 
  AND token = 'gSJmLOb4KRy7fMKqxR+7rLFQDhzQ+Z6u/j2f2GeR+hI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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