SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5ff50bb3285c5f6579d85d36d17c8f92a1af9a9e8239c3276a54a729b6bd270' 
  AND token = 'onDsYSf3WXwvVrDF2GkElsWuJNKscT3+oQLLDBA00+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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