SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f79e49b948d316b448134be8363c144c174c1a97680cb8cefba5540bf0198e0b' 
  AND token = 'TmVNhiQTVx+vm2xKZt5LTELlfoyx56fOsFzg0ua9GiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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