SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f19aa2961d40e388ee5a2168b68b9ecece833493332473127e07ed1d5d63825' 
  AND token = 'gyWCw/WtEe3Rs6izZEnHHEA3WzoBmVeQrVu3IgVsQcs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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