SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f95ae90a388e56d2a350e8f2744076c92400fba6ead3e5dcd47bface9669b6b' 
  AND token = 'OpgnaJgGV6QZR2CvTMrDPKZRO/zy6XHyCJd/0wS8njU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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