SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f685685d7d8f933eaeaaa90f47ac5b1a5ad85082138689a08e5a1ebfa436ad90' 
  AND token = 'OCge0AtJPx9IsugRf9PbErEpZF7UNVAkmeGro7LUWbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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