SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7298d8f4bdd8c7160f1076f916cf3d657cddc14a45a5aea888c1f1f617cc6ccf' 
  AND token = 'uiEdfDYeBToWl2xP83Wc6WaG6Yu6+l0paRys8qq6EYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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