SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b6821746d83a7edafeeff75365bce9b4dff45d28e93e5183b388cd3d0dc1661a' 
  AND token = 'nCzs7O3N+42/7rBIwXO1VgpzR8LnclIb33ZTTZPhhqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}