SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c30d8d64c6c28819c51aad4a5302fc54c3805aefee89fe40e8b098b57c96422' 
  AND token = 'RgyYK7u1euzEMi9gAQVUYYAo8ljBAoj/tj+Q/dVzwbk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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