SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'f729fbd9fe4c67dda7ceae338063b8f818e8e1e05f12ff5fc195073c9029d717' 
  AND token = 'xXQU7JHABBQW9WEaQIKcktkMManm6AGou7WQnbs19rU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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