SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '2a9e3ab647ed050b40fcf567e1ddd56bb46699729b9bd66d4809ec9b6c3a4248' 
  AND token = '8wD9ojkrc4j26cC+8w7o56LAdPveQRdl+CCizd1yW2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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