SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a6511960c057ebe6e6a490b8d08da72b29cd400d1d7f452bce3ca1fb0c1ddc81' 
  AND token = 'HKYypBjDD1zbjNVZA71KVwtzNhKh4nxxdCO+3WuGGJw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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