SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3c6ecba6965b5f355a132199a132b24aaadef70602eada8736d4d96ad107dead' 
  AND token = 'rCCLgbyk6r3tNZ0sQ6blWPhubl31MHadAeFuRZRvwFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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