SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9536a52931571b2195f4c0fc0704c5c9257f322151ecd2b8087688484e649883' 
  AND token = 'CFAUIfzKrrKDlZksubOuvy9r07wTrT1fSkTSg6ZpIi4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00066

JSON explain

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