SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5244694b3646532c5b4904cff142f85e01f815311999c1bbc81eec65b36172cd' 
  AND token = 'YOnCzHQFekBTKE9aXAfsElv9+cG98zwjJFZgbFtTTos=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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