SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'dbe46cb62595ed4ddd40d607f77eb09361424aec7a3f353fbdbffaba05f35cec' 
  AND token = 'h8BSz4nG8zImZnJm2lLtQE+y4hZu+UJNvz0Z+Ab6rz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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