SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '285c7745323119e7dff6f262297449fbbad7dd2ad1681ab08d4da9a3dec7aa94' 
  AND token = 'QMRYDeWdxWRnQcHe4VdQ+SBQrwXrBKWxSNLif6lqRFc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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