SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b184c4558818ea8f4b8bcbcc83e9bc5179e27e8d33919a88c9c7c5322a990a7' 
  AND token = 'JRCk3c9Z92YVdlBUM0plbjf1t//jQEhjcJ53cV+vxdU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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