SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9fd3b3e650cbe924e8dc681fb9ee544b07979b4fe18f208ea11b029319b53361' 
  AND token = 'n3FWLqVpimNciSo2l50pJfLWNjNnYnxQCyypo2oMu2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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