SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9fdbdbed803e160dd7aef8fc6d3baec6615b1ccbf1f6a26bffecf6e351d85e9e' 
  AND token = 'BYqnwDuXJZ5YtzLCnCQXWjNgRbRirY4JUeeTCLgEa+c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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