SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'be435e4ef94ab03f9931cbbf28b2a366aa5904efe118c1c7b7a09bbbff2c7677' 
  AND token = 'AlB8Ht5EexNgk/aiXFRjTa2phwRXhFoYYulp76Obmlg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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