SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11c91365bbb88c09074b239e07f6fdd47597be790e93d682b1428e28d46fca23' 
  AND token = 'uQbSbmy1vxrTwpckC1NWOaFcyZkE9mfXrzbIgIWv38A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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