SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '7e700dde2631f921b8fe336b8dd87a34782fd2915ff2431156ca23d2e53e0476' 
  AND token = 'ulBsfIvx+sFWtfn7cqYGBMo9MyFGCsRELNqFwkmsWRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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