SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7dde8500910156e64d0944454419ef2d4bbd1eb77afc74a935207a5a70a9a16' 
  AND token = 'vTYfWw6I7gLK6fg5Vgp2vYHP4SBwGciKn0ssGdauTeM=' 
  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"
    }
  }
}