SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9ba89868ec2aacf5f1bb5233d32a08966601a68debc720fd928e19528728995' 
  AND token = '9xioA8JnuL1xsj8RfGuO7qpn99fhbEg9X+6Kl8cOIyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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