SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39e8eafd4f915594e5e483b4a07963b26999a7c1784186ea8a61b4580261c5f3' 
  AND token = 'y5nyXYzIyFZGieixFSwJxZ9U7VK9tZe5EtrS95s8wgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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