SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d04943e4ef999f87e6311ecbf8a7a8a9418ac706050a90cf8578e9adfbcc12b' 
  AND token = '5laQgWOgmBjFqTs61qAKpqv0LM0kJYh/LtJBXUzxJ+o=' 
  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"
    }
  }
}