SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc1ad1b54efd3f88149e1be83db5026e340d646b68c09b2cb799247421cd19d5' 
  AND token = 'WCgAN9chvk9DWjuc0VhC5Y7sjVIlpmqx/i3HZzDmCI4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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