SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b828deb1285a02f11550a4ead15c68291bedd4492e6db13178ce261dce7e0c3' 
  AND token = 'xUF0RaGZBxzDRB/0z1ZAokYyBwDPRsmjLfGY9y/CPLo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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