SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '88743943c1a25e1c5afe285e460ed7cc7813a85f4bf617922675140e3902bbc6' 
  AND token = 'KKcFQS4dh2POlHGU54zmMV9X3cjIWbz0rDRQyD5XiAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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