SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bfd9fffebc8168236cbd6896586477af882d55bc86af5645a2e2658c9a06ab9' 
  AND token = 'PFeFdx6jN3XOcW5OVIWN6RFqKKN1SzBdNjPdZ21TSKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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