SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'd56428b12ad79f4942704e577bd66aee20650567132ec96f950f694c5159060b' 
  AND token = 'CVGt/PVUN0VmtJ7whxXj2mU2HFUElRbYEXwh9hwXNM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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