SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e3c3eccf486aee5a46c420d002725b5f990db383162e0a8fc323ed3a142c3afd' 
  AND token = '8OZXR0rKXqQHhjT6scbVBLJlRMEHdkUwsgA83PExGKk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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