SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '544aba1cd412246e72afcf0cd8636951e51e3aa135dded34d220e877731d9bba' 
  AND token = 'vWpxgRP/9UNa6Wj1u9DERgqaxhUC8yvH7YuwwkY6sVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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