SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73fabc5cf67c839580af4f60e05f259ac0b3116f5b4b41b57d3a31f343285778' 
  AND token = 'VxxeU4LIqbdlibtcVkEGdwhY0BWz6KUm+6dW0ODsvOw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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