SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad4ac6d0fab5729a4ca1276f5d3ccd3206fbc9092233bcc81585688c87226fdb' 
  AND token = 'NWBDhSf+2iL48Gaoz+YDdUHYYqCagweDiN2UHECsous=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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