SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61a9e8805610f930b19f247fff2b8fff564e1e37fd269e7202bbae47809d1192' 
  AND token = 'kfS8zzLnEpUb2A3Uu2+JuiyAfUuNocGtpsU/e/ErRmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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