SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '767673facc76fb5e167df82295cf13ddd65e899851896caa26132cf57ef2893e' 
  AND token = 'Ezu0IF5bL4Ng2Wl/gQgBdLocPJ7eAO5NjEHM3aK7lNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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