SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'def83c8f66ff385ac24bc2efdaecf5a68a046149ac67dbc4173a0c2257f98912' 
  AND token = 'RYEZaGyy+B8qP4d2vhXmopZyRcjE2iVz/MPtxDMvJMI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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