SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a23b336ac2fe2886151568ea22a30bab44c0bd00941b7dbe08f32204184c0c09' 
  AND token = 'SZ/pcEl1ZPYGVlZJjm/B6HjF3FA8BVA3+FXgEpu0s6E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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