SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7493538df9315c334fcd72cfab834b63d9b0171926989da6ffb8799d9d19fdcc' 
  AND token = '3Xqjf+zUOm9vqHY7i1ucZwCtWLf8MZ+essDMqVuRxw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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