SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aff01ea542900d54f78ecd3707b6986b27a238569963f0725b753e48dd54c36a' 
  AND token = 'Rg502/NLZB0OtQMQNy1vLJBHszIqOAwrk3EvF9U6c4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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