SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79dbe7c83f34b74bd43695c0bd7aad93b452b406c8e929208228fe5a9713b37b' 
  AND token = 'SRlSb5vybKkGJ8S2Ys0EJ2ydoOdgH79u/lJ9GpZu1/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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