SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '16e5a7fc7e700baa4bc61a55a1e5420c089f9cf8827a1e97e8134975c8c80ec5' 
  AND token = 'XF5w3vyaPRnI7sBdG9Chy8kVRkZwy6XKB1b0lcuGkm0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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