SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '82ace4bc9bf0f5650a5c05ece2e77afa99d9e068bb7586c68215eca6da70cc51' 
  AND token = 'ZzHXWiIZpbNkVCK+G1WXgKdbI842dCzvwj94TghbhSI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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