SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6153962febb46c9606e6823159fedaccb3b2e34bba9c7458a4d38fa5a92ab6cc' 
  AND token = 'uswH+cFwP/sXtJzLWmXlkOXwM4eQIKhMgmpfIBT1DrU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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