SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97ecf91658bd429ed2bbb48eeb8dda10a390e6303c0dd1f7612b5dac499714ea' 
  AND token = 'uj1LmFkyA15qC6+2b69a9txmWfNfYZjfq+XVVTt49YA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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