SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '90bf06803ebf98d870d9b40014920d5bbee68ecf348af29d2a8132de1129416d' 
  AND token = 'Gb9MrsFVg5lJZ2tEQStGtgG/GsYWItlint8DLaTxPs8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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