SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'df30b3c47f5d1494257f77006be49ddafbbc0ae571e5d2e00de8dd316750d9d2' 
  AND token = 'pExgPj5qcuWpMnpFyqgcrvh5XZJ7XjLHkGzj6nVgFVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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