SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1f608b820b50e9c93f49354973699a1c1b5595e73db5b86052a8eaeaa554dfc' 
  AND token = 'MvlAP20q9GjiYjw4GSOmuIQxs9CakqZ5ucAScs/ggpE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}