SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9d7450f4349eb5f5191fb7084bc8b0c748d33308209a846028ed5947348720e' 
  AND token = 'jeuRZcuCngsqVzHhV4iuGdpfql3ZazKmrREtg2pA/3w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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