SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c792a4b8f5f74825dd910d22659c6cc1520c9462420f25485522f4513ed7bf40' 
  AND token = 'MsH88IVOnwg+kuoqsk+FoCxq/PQNfLkcYBqf0u6/B28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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