SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb2397ed1fb4c528f6045fc4c288d486f76df3882fb5b172c632e7a2b59c6b09' 
  AND token = '5J8RjMPX5lFOw7fWZp3NLO1ZnaosRgqT+wfbwUzDKc4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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