SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3765c26f7429cdde63f5c0d81855654a9e769f61d9c6eba471009631e44eae9c' 
  AND token = '+66mifKNQL6A8vqt8rT+qwbFtgTiflLhOz3h21V4ubY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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