SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a7c9f986ea387ade84e918102aa6902f1f1a5f42170c6d4de9f910ea866834cd' 
  AND token = 'US39QulIS9k8Fr8tma0YaD2tsol5p7tRf4crMTz75c4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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