SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dde3c0cb1853526ed22f19ebc2e0906290aada8a8d7caeffd00f22ba0d5ccaf0' 
  AND token = 'hgkVI+uVWg/Wdr8Iqx8dehGKtic3O+r/snmxnEfrI9o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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