SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a923ad7d8ed8ce08ce952b64995797c0435e45467d9edd356edd0b51ab5b9dd0' 
  AND token = 'HOds7sazAAvcQyLFMNniX1we61BnGCQo9uocpahjGyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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