SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '397e434d0b426d7b2bfd31d87fa5d217d6c509b1b1ff9cd40ff90c3822545c28' 
  AND token = 'xq3uJtDs9Fz7vAbkrK0LvWGZuNvkZaqtY5nRbU+DKY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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