SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ed4545e01f85fc05617f10b47b7f9c3d874c8d49603831bb98bfad43f3db036' 
  AND token = 'Jlso98icFysr8BjOCSCktiF0GzIJDnaWV7vSrQyWHf0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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