SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e29ad317bbf7e931e26076254bb54ec05262343ea8d48be4ca42383aa6eecce' 
  AND token = 'prKArhJTlDkzKU8dgMmK6xXXWKIHD5rYor5cIF9zWrU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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