SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '64680fea3618276a85120128bbe31f80026dbfa855fd477d7256127af86fea1a' 
  AND token = 'HeNbJeRohfKGC79tJQ7zcHsv+OPhbdIy9XpxNQ+FMLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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