SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9d9b85d99fc1be2eafb53425e84c1f25f586af65bc7ac7d7343c82f1dbf4679' 
  AND token = 'Sw2jj/u1Z7XvD1rHO+S5z+vbbrdrNQGhtFyKFuClVMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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