SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87d62432a3839ed05a60f6cecd7642382e4f13adc051f5fea696b5cda4068e6f' 
  AND token = 'aawYxn/4UpqTYJ4hjSuJUJUT7xWl6gQId/hmjxWfXAE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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