SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ef1a87712f809c0eed8b1f97e015311becaf4f89511736afad8deb197136dc8' 
  AND token = 'lZqj+Worj+oNymOo43jkGvomA9oZPo81SR2rDXpUaOA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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