SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef749de526f4fb70fec507504796264ce24e0709d67022901932d65a968cbede' 
  AND token = 'qHQ7gsjUcSiuoLjEvtbB2M7/cO9WnvIgczNbfKLZoI4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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