Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd54e927c241e6bcb13ec6ee96ce2500c74cffa78dc2cb2ae3c5c4c28d29bf703' 
  AND token = 't1Axe8pTtZdQ1xjoIkMUr/j81rGHNq1FzNQNB7X2Nks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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