SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '01e84c5c321a1fa429620762cd09b0b55d7d359335d20450fda09b818c0e827a' 
  AND token = '42I+qwjSJh3Bs3tYAZ5pfdX0uOlHKrIyQkrZFlHFLnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}