SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '39f3359d75bb480c4353cdc82cd14290311b01ce13be9717c6a58eb88895a652' 
  AND token = '5vulP3dJQA5rlx9UhlxYp5IZ0JdlIEmlm99BpXOA5rA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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