SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '131484dac849909f9a6512c2f510b1022d805ca076be332f00d7a4fde81c6abe' 
  AND token = 'xRDBzUfXEHc2hHzbZ8eR2BccsxUTzXWvadAP7ZgIJfU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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