SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b7b9557f88808b03292144678a672f139be89db9d667c87d107720db5025518d' 
  AND token = 'E6Lvx9s3rfGIxSTy1fUzV9rT86elca7zv13WnupkI5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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