SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b81c2666d745e750133ce66af3f3ba6a46c796edfd100f93ca88025bb681bffd' 
  AND token = 'XUuOJCSOhSBDysiILFACeesN5qAQ3dcE3ymh1gJ2GCM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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