SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '283cf3b4353354830437207d5e2a47e5b9cdda0e17a542631ea2cdf475dc6683' 
  AND token = 'upJmRqtvSbvui9mnveQn+ZswuLxe9+KYrZBJu8J0y58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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