SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59a6c13333a18dc55e83b103b37832abee5784cd5c165725b72903604593723c' 
  AND token = '+bQjeVP9KrKCvVFWkuJIM9VtEaWi7zhx1m0IDQocvBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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