SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e8ea20f7153015cbff483ee93ebff9cf10ce0aa864b5a2ee2a262fa2647d837' 
  AND token = 'g+Gj/eAd0qFsCAJJNdgvb0Yd+Ir0zaCjA7hjuRiX6lc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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