SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '900962bcf4613d29618d675442b5b9d107098b53c9cc4046dffacdd39c678aee' 
  AND token = 'c3eK+YuIQ7UUuB4ouyfxqlRlwOLC/SjRxWbVWeXazeA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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