SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '677db6d2643af3a5c23a71b656fee4cbdb1230f3c9212f381c388c05670bc3d0' 
  AND token = 'IQIDwSk+T/gobDOfqBePksKRc9lN3CQAVK/3NQdHNG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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