SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a75da58e568bd9e699a3b8e1e3b3d70867a48b6a88d02c5e1e3495aa43102c41' 
  AND token = 'fMkw9DvePuAx8LC4KBoD5ND01YlkcHaDrxqz3x9PI20=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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