SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab0b1ef0df7801f344a6a2be3457362f621db69292f3963bc4b7b9b6ab9833f2' 
  AND token = 'Mi/46wemzHM+oBPhVD556gViXIKgtsZuw+3xvtZPRj4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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