SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c54a1ddb6b7f29448bef62e63fde130153036ef8c7e31f1a8cc6ba0a3b23db4d' 
  AND token = 'UJt595TDhhwgXGOgn+PyRKWDVcnuXC6vhe+hoDSzbRY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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