SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ce51e84682f1449c646f3e9c44d928d7bf91c85fb5f72171b5a8f3fe049333b' 
  AND token = 'JMAs2h8ziUDVLj4JYfcKv8+QYzzRRcWaJqMBiADvsUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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