SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6841abd4e45a1e6ea400b87291e9437bfd5bea40535200eb0a608016e2eca953' 
  AND token = 'hcRPHbkfkLlWhK9jaFka9AdbmqSv1/dxOhhYNqj2PgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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