SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03c1643962ec8dd8a39f120cc0e410572dc46fd9842b8cb898792882bd0e6581' 
  AND token = '4kM/IEWLl+MWNTks/7yBE6sPuKn43EEo9Y3XxzYiyPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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