SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04d838e9e239ee2409532bfebc6285a7c079bc40c6078fae8d1eb06089180cd3' 
  AND token = 'PxLQ39V27TR1JbzwalV+T/262wZTwlklPxdWMbnr7vc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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