SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ac72a36d0a4d6e5fb53cd90a693773250650bf8caa08b0385d02d5475f0b221' 
  AND token = 'XkNQxqAYAjXluaAgRN8grJcNHpMNd0qAJmwPOYxi3eQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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