SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c59b24cbbab1b543cf1b00c6e44811598e7b62cee22ff97795a177c916784432' 
  AND token = 'x689lBgkFBnZD9EAYMwerAolYt/ZKDU1t00hAliKvyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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