SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e79dbb4cba69724befbf5b31a99600177cda0ce939f62dba0c2b5f3fd9a8a32d' 
  AND token = 'hh9Kgrpub8DGuxB7oLJ2RYhBXlImYhAzWpmSpirqLoc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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