SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '174badbd5e9f0eece642e3600a0254b2779799e95ce748ea80ecfae1b79601cd' 
  AND token = 'sKJFEo6BulRjJAszvHss47mk8b6QzVKYC+cwpMjUH7g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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